Speed Up Your Mac with an External SSD

If you have an iMac with Thunderbolt or USB 3 but without an SSD you can boot from a full-speed external SSD without opening the case. It’s possible for that Mac to boot in under 30 seconds and to jump generations ahead for under $200.

Update October 2, 2016: Lots of folks have reported that this works with El Capitan and I’ve used it with macOS Sierra as well. Just follow the instructions as below, using the new installer version.

I have a mid-2011 iMac I use at my office to keep my workspace clean and straightforward. Most of my real work takes places online or on remove servers the OS isn’t a factor that I take into consideration. Nevertheless, Mac OS X  or macOS running on an HDD iMac is SLOW. It can easily take 4 minutes to fully boot to a useful state.

I wanted to move my system device to an SSD to improve that performance. Realizing that opening up an iMac is an absolute nightmare I started looking for external options, and Thunderbolt presented itself as the best possible option for my model. Thunderbolt can transfer at 5Gb/s and USB 3 at 2.5Gb/s. Either of these is more than enough to take full advantage of an SSD. Firewire 800 is also an option for older iMacs, although I haven’t extensively researched it. My mid-2011 model only had Thunderbolt support, so Thunderbolt it was.

LaCie now makes ready-to-go Thunderbolt ($196 at time of writing) and USB 3 ($140 at time of writing) external SSD drives that can be easily connected to your Mac. All you need to do is connect the drive and boot from it (remember, the drive will always need to stay connected, since your Mac will be running from this drive!).

To begin, download the OS X or macOS version you’re using, to do that head to the App Store (command+space and type “app store” to find the application). Go to the product page for the OS version you’re using and click Download, then Continue to download the full Installer. The full installer is several Gigabytes in size, and will take some time to download; it has everything necessary to make a completely fresh installation of Mac OS.

App Store

If you don’t want to end up with a totally “clean” new Mac OS X/macOS install, use this time to make a full Time Machine backup that can be restored into the newly install copy of Mac OS X/macOS once it’s completed. Learn how to set up Time Machine with Apple Support.

Open the Disk Utility (command+space and type the name of the application) and click on your NEW external SSD and choose the Partition tab, and choose 1 Partition from the drop-down menu. Select Mac OS Extended (Journaled) as the Format and Name the new partition whatever you’d like.

Disk Utility


Click the Options… button and choose GUID Partition Table as the partition scheme and click OK. Finally verify your choices one last time and click Apply on the Disk Utility window to commit your changes to the new disk.

Partition Scheme

Go ahead and start the OS X/macOS installation wizard, and continue though the first screens until you reach the disk selection step. Here, select “Show All Disks…” and choose the new external partition you created earlier, finally selecting “Install” and confirm your administrative password to begin installs OS X/macOS on your new drive.

Install Disk Screen

If you’re restoring a Time Machine backup, once the new OS is installed shut down your Mac and hold down Command+R while booting it up again. You’ll see the Recovery Options window, and from here you can select “Restore from a Time Machine backup” and follow the steps to restore your files and preferences from the backup you took earlier to your new install. If you find any Applications missing from your restored system you can usually copy them from the Applications directory of the internal hard drive that will still be available from inside Finder.

Your Mac should begin to use the new External disk to boot from automatically from now on. But if it doesn’t you can press and hold the Option key while starting your Mac to select which disk you want to boot from. You can also change the default startup disk in the Startup Disk preferences screen by booting into your new installation, clicking the Apple icon in the top-left corner and selecting “System Preferences…” then “Startup Disk” and choosing your external SSD drive in the list.

Mac OS X Startip Disk Preferences Window

Show CommentsClose Comments


  • Richard
    Posted October 29, 2013 at 3:39 pm 0Likes

    Thanx for the article, really, really helpful! I consider installing Mavericks on an external SSD drive connected via Thunderbolt to my Mac Mini (Late 2012) and booting MacOS X from it…. I am just curious how future MacOS updates via App Store will be installed. At the moment, the App Store will only install apps (and so the future MacOS X update) on my internal HD (I think one cannot choose a different location). Do you know if this behavior going to change if I set the external SSD as the new boot drive? Will apps/MacOS updates from the App Store be installed automatically on the drive you selected as your boot drive? Hope you can help me. I am just thinking about future MacOS upgrades on the SSD and if it will work..(Sorry for my english, I am from Vienna)… Thanx in advance! Richard

    • Robin Monks
      Posted October 29, 2013 at 3:47 pm 0Likes

      Hi Richard!

      Yes, the App Store will use your boot drive to install apps to by default, this means that system upgrades to future versions of Mac OS X will also work just fine.

      • Richard
        Posted October 29, 2013 at 4:22 pm 0Likes

        Thanx so much for the quick reply! This is great news! Looking forward to this! 🙂 Thanx again!

      • Gordon Pilcher
        Posted May 22, 2014 at 1:29 pm 0Likes

        Hi recently I upgraded to mavericks and since then my iMac which also a mid 2011
        Model Name: iMac
        Model Identifier: iMac12,1
        Processor Name: Intel Core i5
        Processor Speed: 2.7 GHz
        Number of Processors: 1
        Total Number of Cores: 4
        L2 Cache (per Core): 256 KB
        L3 Cache: 6 MB
        Memory: 4 GB
        Boot ROM Version: IM121.0047.B1F
        SMC Version (system): 1.71f22
        Serial Number (system): C2QJ110JDHJN
        Hardware UUID: 1B8B3158-A560-5E04-8F44-44AB47DBD4C2
        I’m running a broadcast program call radio logic DJ http://macinmind.com/?area=app&app=radiologik&pg=info
        The thing runs 24/7 and was getting a little boggy at times, so what I am planning is another16Gb memory as it is easy to install. The thought of tearing apart put me off a bit. If was an old PC no problem. However, these are bit fiddly. With software, constantly reading the drive for the application and reading the iTunes folder. I was thinking that could be causing the drive not to buffer fast enough. But with applications already installed on the current drive like adobe audition CS6 and other stuff I use to keep it running seamlessly. I’ve ask the guy who writes the software but he doesn’t use some of the applications I do, will I need to reinstall to the new boot drive if I’m using an external drive such as the LaCie 1.0TB Rugged USB 3.0

        • Robin Monks
          Posted June 6, 2014 at 4:15 pm 0Likes

          I sadly don’t really know what to tell you, it does sound more like a software issue than anything else. OSX should handle buffering reads from the drives itself if the software is written correctly.

      • Kevin Hui
        Posted January 15, 2015 at 2:45 pm 0Likes

        Hi Robin,

        Thanks so much for your great article, very useful indeed.

        May I know how you managed to “shrink” your data into the SSD? I notice you internal HD stored more than 500GB of data but your SSD was only 128GB.

        Many thanks.


        • Robin Monks
          Posted January 15, 2015 at 7:17 pm 0Likes

          Hi Kevin, I didn’t actually have 500GB of data, just that was the size of the drive. OSX only takes about 15GB after install on your SSD.

          • Kevin Hui
            Posted January 16, 2015 at 3:15 pm 0Likes

            Thanks so much for your prompt reply Robin.

  • Michael Zaplatosch
    Posted November 14, 2013 at 11:10 pm 0Likes

    How has this worked out so far? I am interested in a 27 inch iMac but this will keep costs down. Is there a difference in performance doing it this way?

    • Robin Monks
      Posted November 21, 2013 at 1:05 pm 0Likes

      I’ve used this setup for about 10 months now; through two versions of OSX. I’ve never seen it slow down and it remains speedy. I don’t have a pure test case against the same model with an SSD for a comparison; but I can boot to desktop in 20-25 seconds and never experience lag opening applications. This compares to about a 5 minutes boot with the original HDD.

      • Michael Zaplatosch
        Posted November 21, 2013 at 2:07 pm 0Likes

        Hi Robin, thanks for the update. I have done this, and yes much better that a traditional HD. The enclosure I am using though is limiting the speeds to 200mb/150mb read and write. The ssd is more than able to hit 500mb in both directions

      • Gregg
        Posted January 14, 2014 at 4:41 am 0Likes

        I put a LaCie thunderbolt drive on my new Imac. First I put Mavericks on it and Adobe creative suite, the system continually crashed. Finally it wouldn’t boot at all and i had to put in the shop under apple care. Now I have mt. lion on the external drive and the system still seems very unreliable ( compared to the 2006 mac pro w/OWC SSD which never crashed …. kinda sorry I ever moved off it).

        Every once in a while the system hangs when trying to shutdown! I sure would have to go back to booting off the hard drive, it is so slow that my 2006 mac pro runs circles around it. Any suggestions .. Drive updates ? Do I have a lemon SSD or imac?

        • Robin Monks
          Posted January 21, 2014 at 1:56 am 0Likes

          It sounds like an issue with your external drive or enclosure. Try using a tool like Drive Speed Test (http://itunes.apple.com/us/app/id425264550?mt=12) and see what performance you are getting from the internal and external drives. It may be your enclosure isn’t optimized for SSD drives or isn’t Firewire 800. You didn’t mention what type of interfaces your Mac has available, but if you have USB 3 or Thunderbolt available you could use one of those enclosures.

          • gregg
            Posted January 21, 2014 at 6:22 pm 0Likes

            Robin thanks for responding. The SSD is a Lacie Ruggged using the thunderbolt cable that came with it. Nothing special. The backup drive is a WD 3.0 my mac book 3.0 nothing special. The last item is a Macally super speed enclosure with a 7200 1.5 TB disk that was running in my old mac pro the disk ( it runs like a champ in the old computer.)
            I grabbed the tool you suggested, ( not that I know what all the numbers mean) and it passed the PAL/NTSC
            here is a table with Read/write speed. the only thing that wouldn’t pass is one of those little Usb sticks with a flash on it ( I did that for fun,…)

            test | internal mac hard drive | wd 3.0 external | MCally s3.0 external | LaCie thunderbolt SSD
            PAL | 102/101 | 123/123 | 95/96 | 101/352
            NTSC 121/120 | 146/146 | 112/114 | 120 421

            I found this repeatedly in the Crash log reports…..

            panic(cpu 1 caller 0xffffff802c2fad38): “hfs_swap_HFSPlusBTInternalNode: catalog key #9 invalid length (8236)\n”@/SourceCache/xnu/xnu-2050.48.12/bsd/hfs/hfs_endian.c:520

            Any ideas from this I can share with Apple Engineers?

        • Robin Monks
          Posted March 5, 2014 at 12:59 pm 0Likes

          It sounds like a lemon SSD based on your clarification. I’d try re-formatting it and following the steps above again.

        • Sascha
          Posted June 2, 2015 at 3:49 am 0Likes

          I had exactly the same problems with all products from LaCie, when used via Thunderbolt. The same disks used via USB3 worked fine, while via Thunderbolt it came to many crashes and sudden reboots of the system. It seems that the LaCie engineers have trouble with the Thunderbolt technology, and unfortunately LaCie is not known for supplying Firmware updates to fix such problems.

          • desisn
            Posted November 19, 2017 at 11:40 am 0Likes

            If you have a USB 3.0 capable Mac, i can only recommend using it with an Transcend USB 3.0 external drive adapter and purchasing a 2.5 inch SSD for it. I have this running without a problem in my iMac as the system disk and it is very fast 400 Mbs read speed. This is the external case I got: Transcend StoreJet 25CK3 2.5″ Storage Enclosure – I had a different one before and it constantly crashed so be sure to get a good one like this.

            Also it only works fast with USB 3.0, so old Macs will not be able to work with it.

  • mrdary
    Posted November 27, 2013 at 1:42 am 0Likes

    Great article! I’m really excited about trying this approach. Do you still use the internal HD on your mac for files? I am thinking about doing this so that I can get the benefit of an ssd without buying a new iMac with a fusion drive…

    • Robin Monks
      Posted November 27, 2013 at 3:41 am 0Likes

      Yeah, I have the 1TB internal drive for file storage now.

      • KM
        Posted July 18, 2014 at 2:05 am 0Likes

        Hi Robin,

        Thanks for the great article. I’m planning to do the same setup as you. I’m curious to know are you able to format or delete ALL the contents off the internal drive completely once Osx is fully running on the external drive.
        I had a problem doing this when i upgraded my macbook pro to ssd os. Somehow it wouldn’t let me format the drive because it had an OS in it evnthough the OS was running on my new internal ssd. I physically had to remove the old internal spinning drive put it on a usb caddy, format it thru my imac 2011 and put it back into my macbook pro.

        any insight or tips you can give me?

        • Robin Monks
          Posted July 27, 2014 at 6:06 pm 0Likes

          Odd, I was able to use Disk Utility to format it without issue. Anyone else seen the issue Kris is describing?

  • Andy
    Posted December 4, 2013 at 6:00 pm 0Likes

    Robin, thanks for this excellent article. Do you think that a 120GB SSD is sufficient to host the OS and typical apps?

    • Robin Monks
      Posted December 10, 2013 at 1:29 pm 0Likes

      It depends on what type of user you are, honestly. It would be sufficient for me, and I believe for most people. If you have a lot of apps or a number of large apps (the entire Adobe Creative Suite) for instance that you want to run from the SSD, you’ll want something larger. The great thing with this method though, is you can still put some apps on your old internal hard drive where speed isn’t an important factor.

  • ovenlite1
    Posted December 10, 2013 at 9:32 am 0Likes

    Quick question, if I used this method to install mavericks onto an SSD with a USB adapter, could I then replace the internal HDD with the newly created boot drive? I’m getting an SSD for my macbook pro and want to do a clean install of Mavericks. thanks!

    • Robin Monks
      Posted December 10, 2013 at 1:34 pm 0Likes

      I wrote the article specifically for those not wanting to open their computer, but, you could. If you intend to replace the drive it’s trivial to make a USB boot drive with the Mac OSX installer from your existing install ( http://osxdaily.com/2011/07/08/make-a-bootable-mac-os-x-10-7-lion-installer-from-a-usb-flash-drive/ ), swap the drives, and then boot from your USB stick to perform the install directly to the SSD.

      • Drew
        Posted April 3, 2015 at 10:02 pm 0Likes

        Just a FYI some late 2009 IMacs have internal temp. sensors on the factory installed standard drives. If you replace the factory drive you will not have a sensor input capability and the sensor will default and run the internal fan at high speed all the time, quite annoying, I have yet to find a way to defeat the missing sensor input?

      • Brendon
        Posted October 7, 2015 at 5:38 am 0Likes

        Robin, many thanks for this article. I successfully attached SSD externally. Everything looks good and machine performance increased tremendously!. However I have one issue with time machine. I had external hard drive for time machine back up. It has been used as backup since September 2011. I had not restored any file before installing SSD externally. After installation of SSD time machine is still on, however it need more space to back up. Now time machine is not backing up because of less space available. I don’t see any old back up. Could you please suggest how to restore my very old photos, music etc. Thanks!

    • jcyph3r
      Posted September 5, 2014 at 2:41 am 0Likes

      The answer is yes. I have done that several times.

  • pierdus
    Posted December 14, 2013 at 9:52 pm 0Likes

    Is there any chance to disable the internal HDD when I successfully run on external SSD? It is too loud and I will appreciate that there is any chance to completely disable it and never hear about it in the future. Any ideas how to do it?:)

  • Robin Monks
    Posted December 16, 2013 at 1:55 pm 0Likes

    Although the drive will spin up at start as long as it’s connected to power, it should automatically spin down after a few minutes and start down as long as you don’t mount it.

  • rickyzhang82
    Posted December 17, 2013 at 12:27 pm 0Likes

    Can you enable trim for external ssd? Btw, can you post black magic disk test result for your ssd? Thanks in advance

    • Robin Monks
      Posted December 26, 2013 at 4:48 pm 0Likes

      For more modern SSD controllers TRIM is no longer as important as it used to be, usually only affected speed a little rather than drastically affecting the speed and shortening the product life as it used to. If you have an older SSD or want to enable TRIM anyways (it really can’t hurt anything), you’ll need a third-party tool (OSX only turns TRIM on automatically for Apple-branded drives). This tool (http://www.groths.org/software/trimenabler/) allows you to turn on TRIM for free, and can give you more details stats for a $10 license.

      I’ll post stats on my iMac in a few days after the holidays.

      • Robin Monks
        Posted January 24, 2014 at 6:10 pm 0Likes

        For the curious, I did a comparison and enabling TRIM for me made no difference to the drive speed. I see 350MB/s writes and 500MB/s reads from my external SSD drive over thunderbolt.

        • Jacques
          Posted March 5, 2014 at 11:00 am 0Likes

          Quick question – did you get these read & write speeds by using a La Cie Thunderbolt SSD on the mid-2011 Mac? That sounds VERY fast – I’m considering getting the LaCie 120Gb rugged drive to use on my mid-2011 iMac and hopes that it will give me marked better performance when using Photoshop and Lightroom

          • Robin Monks
            Posted March 5, 2014 at 1:01 pm 0Likes

            This is a Seagate thunderbolt enclosure. It originally contained an HDD, so I popped the enclosure open and replaced the disk with an SSD myself. You should see similar results from any well made thunderbolt device with an SSD already built in as well.

        • rickyzhang82
          Posted March 9, 2014 at 6:47 am 0Likes

          I’m not sure thunderbolt. But USB 3.0 doesn’t support trim command. Overtime, trim may affect write speed if stale deleted page is growing. In any case, we will see how it affect write performance in longer time.

          BTW, could you post blackmagic disk speed test result? I got 2013 21inch iMac. I’m struggling if I should take the risk to replace spinning disk with SSD or do it in your way.

  • Justin
    Posted December 17, 2013 at 8:48 pm 0Likes

    This may be a foolish question, but I just installed Mavericks successfully on my external ssd, and I’m now unsure how access my internal drive. In my head, I figured I could boot from the ssd and run programs and store files on the internal. Is this the case? Might I be doing something wrong?

    Thank you for the detailed article- it worked perfectly.

    • Robin Monks
      Posted December 26, 2013 at 4:40 pm 0Likes

      You can do exactly that; if for some reason the old internal drive isn’t showing up in Finder you can open the Disk Utility and mount it manually. It should remember it after you’ve mounted it the first time.

  • Nabil
    Posted December 21, 2013 at 3:18 am 0Likes

    Hi, I have the new Imac 27, I boot a clean install OS X mavericks with a External 250g SSD, through USB or Thunderbolt cable?

    • Robin Monks
      Posted December 26, 2013 at 4:39 pm 0Likes

      If it’s a USB 3 enclosure plugged into a USB 3 port (with a USB 3 cable…) you can use it or the Thunderbolt. USB3 is a bit cheaper, but then you end up always having one of your USB ports filled. If your iMac doesn’t have USB 3 support, you must use the Thunderbolt as USB 2 simply isn’t fast enough.

      • Angus Meryon
        Posted October 26, 2014 at 8:38 pm 0Likes

        Dear Robin

        I’ve followed this with interest and am planning a similar project. Thing is, I have a mid-2007 24 inch iMac which has USB 2.0, not 3.0 and no Thunderbolt connection. I want to entirely run my life from a new SSD drive (not bought yet!), i.e. to boot from it, access all files, apps and programs from it.

        Will this work, do you think?
        Many thanks

        • Robin Monks
          Posted October 26, 2014 at 9:03 pm 0Likes

          Do you have Firewire 800? If you do you can use a Firewire 800 enclosure. USB 2.0 will NOT work for SSD as it’s way too slow.

  • David
    Posted December 22, 2013 at 6:57 am 0Likes

    If I install a new operating system on an external SSD drive using thunderbolt do I have the option to boot from the hard drive within my iMac?

    • Robin Monks
      Posted December 26, 2013 at 4:37 pm 0Likes

      You can; press and hold the Option key while starting your Mac to select which disk you want to boot from. You can also follow the directions in the article to use Startup Disk preferences.

  • Pat
    Posted December 22, 2013 at 2:26 pm 0Likes

    Do you have Mac OS X on both Internal HDD and External SSD?

    • Robin Monks
      Posted December 26, 2013 at 4:35 pm 0Likes

      Not anymore, I removed Mac OS from the old internal disk so I’d have more space for storage. That said, noting prevents you from “dual-booting” your Mac between the two drives, and even using a different version of OS X between the two.

      • Stephen
        Posted January 20, 2014 at 10:27 pm 0Likes

        Hi – great article, I just ordered a 120gb LaCie Thunderbolt SSD and will be setting this up tomorrow night (2011 Mac Mini). One question – how do you remove Mac OS from the internal HD, as you indicated in this reply? I’d like to do that, to free up space on the internal HD for file storage. Thanks!

        • Robin Monks
          Posted January 21, 2014 at 1:49 am 0Likes

          You can use Disk Utility to format the Internal HDD once you’re booting from the External SSD.

      • Jay
        Posted May 8, 2014 at 11:42 am 0Likes

        What is the best way to remove the OS from your internal drive once you are booting off the SSD?

        • Robin Monks
          Posted May 8, 2014 at 12:11 pm 0Likes

          You can use the Disk Utility to format the internal drive, make sure you have all the necessary backups before doing so.

  • Robert
    Posted December 23, 2013 at 5:25 am 0Likes

    Thanks for posting your experience with something I’ve been thinking of doing. I have a Superduper clone of my internal drive and was wondering if after installing a clean Mavericks on the Thuderbolt drive, is there a way to migrate just the apps and settings from either the internal drive or Superduper clone?

    • Robin Monks
      Posted December 26, 2013 at 4:31 pm 0Likes

      Depends on the Application; many will use user-specific folders so you might lose settings (or license keys!). If you want all your apps back the best way is to do a full backup and restore to a large-enough SSD before booting from it.

  • James
    Posted December 25, 2013 at 11:08 pm 0Likes

    Hi Robin!

    Superb article, thanks so much.

    I want to do this on my late 2012 iMac, one thing confuses me. Why must I perform a time machine backup? (I don’t have another external to do this too). Surely when I boot from the new drive, all my files/settings will be on the old internal drive for me to drag and drop or use how I want?

    Second to this, once I’ve moved the apps over that I want the benefit of ssd from, how can I ‘clean up’ the internal drive so it’s purely a storage drive and not a full os install?

    Basically I’m worried I’m going to have to buy TWO drives (one ssd to boot from and another hdd to timemachine before I embark on this process).

    Thanks so much for answering,


    • Robin Monks
      Posted December 26, 2013 at 4:34 pm 0Likes

      You’re correct in that all your old files will still be on the Internal SSD and you don’t strictly /need/ to make a backup to transfer over files if you know what you’re doing. The reason I recommend Time Machine is because it’s super-easy and makes it nearly impossible to lose data. This is a case of writing instructions to be as repeatable and easy-to-use as possible (and backups are always a good thing!). If you feel you’re capable of copying the files over yourself from the Internal HDD to External SSD feel free to do so.

  • Jason
    Posted December 26, 2013 at 8:06 pm 0Likes

    Hey Robin, I appreciate the article! I was actually chatting with a Geek Squad member at Best Buy about booting to an OS on an external drive and he said it couldn’t be done… glad I looked into it further since I was pretty sure it was possible.

    I want to get this setup so I can bring my work MacBook Pro (currently a late 2011, but I’m due for an upgrade) to run FinalCut for some video editing, but I want to keep this project separate from my work stuff. Do you think there will be any performance issues running video editing software?

    Here’s the specs on my machine:

    2.4 GHz Intel Core i5, 8 GB memory, Intel HD Graphics 3000 512 MB, running OS X 10.9

    My other problem will be how to hook up 2 HD external monitors when the mini display/ThunderBolt port already in use.

    • Robin Monks
      Posted January 3, 2014 at 3:49 am 0Likes

      Hey Jason! You can install the OS on the external drive and dual-boot; using the internal HDD for work and the External SSD/HDD for your own machine and applications. Final cut should run just fine on an external drive; just make sure it’s large enough!

  • Darren
    Posted January 1, 2014 at 7:33 pm 0Likes

    Hi Robin,

    My 2009 iMac internal HD starting giving me trouble so I followed your advise and went ahead with an external SSD, so far I’m very impressed.

    Just wanted to say Thanks

  • Sam
    Posted January 1, 2014 at 10:35 pm 0Likes

    Hi Robin.
    I wonder if I can do this with my iMac that has only Firewire and USB2. My purpose it to download Mac OS X Mountain Lion on External Drive, restore everything from my Airport Time Capsule, and access the Applications, and data from home and office computers. Do you think it is doable to
    1) Setup with Firewire
    2) Utilize applications that are uploaded on external hard drives.

    • Robin Monks
      Posted January 3, 2014 at 3:47 am 0Likes

      You should be able to use FireWire, just make sure it’s a FireWire 800 enclosure. Applications on external drives will run, although they might add files to the user folder on your primary drive regardless of where they’re installed.

    • Nabil
      Posted January 3, 2014 at 4:07 am 0Likes

      Which ssd system can i buy with the conectiob cable. To put the System on it?

  • Mavirek
    Posted January 5, 2014 at 6:14 am 0Likes

    I have a 24-inch, Early 2008 iMac with FW800 available. Will I benefit speed-wise from using the following as my primary (external) drive: MiniPro 480GB FireWire 800, USB 3.0 Portable Solid State Drive SSD (Mac Version) by Oyen Digital? My current internal HD keeps running out of memory (not storage space). I have to keep clicking the Clean Memory app ever so often to keep my iMac from stuttering.

  • Giorgos
    Posted January 6, 2014 at 10:18 am 0Likes

    Hello Robin!

    Thank you for this great tutorial! I would like to ask what model of ext SSD did you use on this? What is your opinion in using http://www.highpoint-tech.com/USA_new/series_RS5212-overview.htm (with an SSD off course :)) ?

    Thanks again!

  • Matthew O'Connell
    Posted January 11, 2014 at 4:09 am 0Likes

    Great information! I just fired up a new 27″ IMac today and purchased the Lacie 120GB Thunderbolt SSD. This is all new to me. After I install the Mavericks OS on the SSD, should I also install core applications there too? What will give me the greatest speed boost?

    • Robin Monks
      Posted January 21, 2014 at 1:53 am 0Likes

      Any common applications you use should be installed on the SSD, truly “core” applications will be installed with OSX. Any application will start faster off the SSD, so, prioritize what you use most often.

  • Christian Smith
    Posted January 16, 2014 at 9:52 am 0Likes

    Great piece: huge thanks. I just installed the Lacie Rugged 256GB external SSD and it went just like you said. And the performance boost is astonishing – like a new computer. I had no idea how much a conventional disk drive holds back performance on a modern system – surely SSD has to become mainstream or there’s no point increasing performance of the other components. A couple of small points. I bought a Thunderbolt drive for my Mac Mini only to find that, of course, the port is used for the display (duh!). But the USB 3 seems to work just fine. A nice touch for the Lacie is that includes cables for both. Also, at the risk of stating the obvious, to make the Time Machine reinstall really easy, which it is, you will need to get storage used on your existing hard drive down to the same or below the capacity of the new SSD. So you may have to back up some stuff manually (probably media files), delete it from the drive, then do a Time Machine backup, use that for the reinstall and then manually copy back that stuff you deleted. That’s what I did anyway and it worked a treat. Thanks again, Robin.

    • Kobe
      Posted July 6, 2014 at 9:04 am 0Likes

      Can you please plost a black magic speed test with the Lacie rugged thunderbolt ssd?

  • Andy
    Posted January 18, 2014 at 7:12 pm 0Likes

    Great article everything worked perfectly except how do I only use the external as boot drive and keep using the internal for user files. My problem is everything boots just fine but the files ie iTunes pictures and other user files on my internal hdd are not visible unless I go into the mac internal hdd. It’s like they are not working together. The internal hdd is mounted and not encrypted.

    • Robin Monks
      Posted January 21, 2014 at 1:59 am 0Likes

      Your user directory will be forced into the disk you boot from (in your case the SSD). To keep your iTunes music library on your Internal HDD follow the Apple support document here: http://support.apple.com/kb/HT1589

      • David
        Posted December 25, 2014 at 5:48 pm 0Likes

        is there a way to direct all applications on the SSD to use the internal hard drive for storage. The article referred to only applies to iTunes. What about iMovie and iPhoto?
        Great article.

  • John Tanios
    Posted January 19, 2014 at 3:42 am 0Likes

    Hi Robin, great article.

    Im just wondering if this scenario could work. I leave the tradition HDD with osx installed on my iMac but use a ssd with thunderbolt for external apps like cs6 to speed the design apps. Would that work or would i need the whole operating system and apps to be on the ssd to speed things up? i don’t mind if boot time is slow i just want the apps n games to run faster.

    Also do you think opening up the computer and installing the ssd internally would be faster than through thunderbolt? Thanks Heaps

    • Robin Monks
      Posted January 21, 2014 at 2:01 am 0Likes

      Your best bet by far is to run the OS on the SSD, since CS6 uses system libraries to run it won’t run at full speed on an SSD unless the OS is on an SSD as well. Thunderbolt is actually direct enough that the different between an internal installed SSD and an SSD over Thunderbolt would be almost imperceptible.

  • Michael
    Posted January 24, 2014 at 4:36 pm 0Likes

    Thanks Robin. This is extremely helpful. Doing the install tonight!

  • Dmitry
    Posted January 26, 2014 at 12:16 pm 0Likes

    Thanks for the article. It works totally awesome!
    I’m wondering. If I can use as a boot disc for multiple computers from time to time? I have my personal MBPro (mid-11) which I use mostly outside, and iMac at home. I would love to have a single working MacOS for both devices. Will it harm to a disc somehow to boot with multiple computers from time to time?

    Thank you so much!

    p.s It seems like working now, but just not sure if it’s okay to do that.

    • Robin Monks
      Posted January 26, 2014 at 2:59 pm 0Likes

      It should be fine; your user account is on the SSD and should work wherever.

      • Dmitry
        Posted January 26, 2014 at 3:00 pm 0Likes

        Thanks, Robin!

  • Howard Jachter
    Posted February 6, 2014 at 6:07 pm 0Likes

    Brilliant! Works like a charm. Used Lacie Porche Design 9223 slimline USB 3.0 ($139 on Amazon) for better than 1000% performance increase on late 2012 iMac. Night and day! You are correct USB 3.0 is completely adequate (save $60 vs. Thunderbolt).

    • Jeremiah Lowder
      Posted March 28, 2014 at 7:59 am 0Likes

      That was my question. I am torn between USB 3 and thunderbolt and was wondering if there were any benefits to using a thunderbolt drive, other than daisy chaining, which I don’t plan on doing. If you see this reply could you let me know how you’re doing, now that you are a month or so into using it?

  • Zer0
    Posted February 7, 2014 at 11:11 pm 0Likes

    Straightforward article mate! You reckon it would work if one would install Mavericks as described and then simply put the SSD drive into another mac? I’m thinking of trying this with latest Mav + an older MacBook Pro with an internal SSD. The problem is that in the pro the CD drive broke and no USB installation method seems to work either. Will give it shot.. 🙂 would be interested to hear your opinion tough.

    • Robin Monks
      Posted February 8, 2014 at 1:31 pm 0Likes

      If the OS will work with the machine it /should/. Then again, the USB install method documented here should work with the MacBook Pro as well.

      • Zer0
        Posted February 8, 2014 at 3:37 pm 0Likes

        Na, sadly it didn’t – well at least not with 10.6 – 10.8, haven’t tested with 10.9 yet. All others left me with the “still waiting for root device” upon bootup – assuming the USBroot drivers are not included in the installation media as per usually you do it from online sources.

      • Zer0
        Posted February 8, 2014 at 3:41 pm 0Likes

        Whoops sorry i misunderstood you. Haven’t created a USB root device for the MBP – it’s my father’s and would be unnecessary fuss to try and tell him to carry around an external drive of which he boots from 😉

  • Rob
    Posted February 9, 2014 at 11:43 am 0Likes

    i have cloned my mac mini to an external SSD – WD My Book Studio. I find it much SLOWER than using the original hard drive. Why could this be?

    • Robin Monks
      Posted February 11, 2014 at 9:37 pm 0Likes

      Firstly, it has to be an SSD, looking at the product page the WD My Book Studio is an external HDD. Can you link to the product page of the external device you own?

  • Howard Jachter
    Posted February 24, 2014 at 7:30 am 0Likes

    Hi Robin — great solution! Saved me a ton of time when I found the late 2012 iMac I purchased could not be easily upgraded with an SSD.

    I connected LaCie Porsche Design P’9223 USB3.0 Drive. Machine performance is increased by order of magnitude after re-installing/booting Mavericks from SSD. Generally appears that USB 3.0 works pretty well. However, have encountered interesting/very frustrating problem running Parallels Desktop 9 hosting Win 8.1.

    When I run OSX, Parallels, VM; all from SSD, VM freezes frequently — to the point that it is unusable. Windows disk utilization hits 100%, — sometimes for minutes even though nothing much is happening with user apps on Mac or Windows. The Mac disk utilization and resources are not significantly impacted — just Windows. Windows task manager only indicates that the demand for disk resources is coming from SYSTEM.

    When I relocate the Parallels/Windows VM onto the Mac hard drive, freezing behavior disappears. Running both Parallels and VM from the SSD is about twice as fast compared to hard drive VM. Obviously, SSD is the preferable solution but not sure how to make it work for VM’s.

    I’m sure there are others implementing who are implementing this to better support VM performance.

    Sure would appreciate any insights/solutions…


    • Robin Monks
      Posted February 27, 2014 at 8:29 pm 0Likes

      The only thing I can think of is that Windows might be trying to manage the virtual disk in ways the SSD doesn’t know what to do with. I can’t think of any reason offhand why it would cause this behaviour so I can’t offer much in the way of advice. Perhaps someone else using Parallels on an SSD can offer insight.

      • Howard Jachter
        Posted March 3, 2014 at 9:22 pm 0Likes

        Yeah. Seems to be related to virtual memory management. Freezes now occur primarily when switching applications, I increased the resources devoted to Parallels VM and decreased the occurrences and magnitude of the freezes so VM is very usable as long as I don’t use too many apps at once…. not easy for a developer though!

        Interestingly, when I use OSX/Parallels/Win8.1 on Macbook Air with the identical VM, OSX and Windows both run flawlessly. Obviously, there is a difference between internal and external SSD. I’m thinking it may be due to the speed of the USB 3.0 connection. Maybe it’s not fast enough for memory page swaps.

        That would lead me to hypothesize that Thunderbolt would be a requirement when user plans to run virtual machines on OSX. However, I can’t confirm this hypothesis without additional testing using the Thunderbolt version of the Lacie SSD.

        Anyone have experience with OSX/Parallels/Windows 8.1 over Thunderbolt SSD?

        • Stephen
          Posted March 3, 2014 at 10:01 pm 0Likes

          Yes – Parallels works great on an external Thunderbolt SSD. But I’m using it with Window 7, not Windows 8.

          • Howard Jachter
            Posted March 4, 2014 at 9:42 am 0Likes

            Hey Stephen, are you booting OSX and running Parallels/Win7 all on SSD?

          • Howard Jachter
            Posted March 4, 2014 at 9:45 am 0Likes

            Also, how much Parallels RAM have you devoted to VM?

            BTW, thanks your your response!

          • Stephen
            Posted March 4, 2014 at 2:36 pm 0Likes

            I only devote 1GB RAM to the VM (out of 8GB). I previously tried it with an external HDD over USB 3, and had the same kind of freezing which you describe. Since moving it to the Thunderbolt SSD, it’s been mostly fine (I’ve had one or two freeze-ups, but nothing regular). I originally assumed this improvement was due to the performance of the SSD vs. the HDD, but in hindsight that doesn’t make sense because the VM ran fine on the internal HDD (just slower, like OSX) – so as you suggest, it is possible that USB 3 can’t quite handle it for some reason. Then again, I don’t put big demands on my VM – mainly MS Office, to use VBA macros in Excel which don’t function in Office for Mac. Perhaps your use of the VM is more resource-intensive. But I wouldn’t be surprised if you got the same improvement from switching to Thunderbolt that I did. I also noticed that OSX runs a little smoother via Thunderbolt than USB 3 (although it was OK on USB 3) – so worst-case scenario, you would get OSX running even better if you get a Thunderbolt LaCie (LaCie is also the one I’m using).

            I did some Google research to see if there was a logical explanation for this, and the best I came up with is that Thunderbolt supports Native Command Queuing (NCQ), which USB 3 does not. Although NCQ is apparently more important for HDDs, it also affects the performance of SSDs by allowing the SSD Controller to complete commands concurrently and some other things which are too technical for my brain. NCQ is apparently most important for large files, and a typical VM is a large file in OSX (mine is more than 30GB). In any case, it sounds plausible that the problem could be something to do with this non-support for NCQ on USB3. (SATA also supports NCQ). But then again, that’s just a theory I just made up.

    • Howard Jachter
      Posted March 4, 2014 at 7:46 pm 0Likes

      It is memory paging that’s causing the freezes and the fact that USB3.0 is inadequate to support it. I have no idea if it’s related to NCQ as Stephen suggests but for whatever reason, the USB 3.0 interface does not support direct memory paging to the disk very well.

      To verify that hypothesis, I reduced the RAM allocated to the VM to 1Gb — which should increase the “freezing”. It did… big time. The VM became unusable since disk I/O was usually between 99% and 100% utilization. Then, I allocated 4Gb to the VM (out of the 8Gb total). The freezing problem virtually disappeared and VM disk utilization only hits 100% when I place very large I/O demand on the SSD (like moving/downloading files into memory). As soon as the demand is met (e.g., by loading a large application) the disk I/O bandwidth utilization returns to low levels. For OSX Mavericks running Parallels Desktop 9 running Windows 8.1, 4Gb RAM pretty much eliminates paging freezes.

      So, my modified conclusion is: “USB 3.0 connected external SSD is adequate as long as paging activity is reduced by allocating sufficient RAM to the Windows virtual machine”.

      I expect this would be true of Linux, other Windows versions etc. but each has different memory demands so the optimum memory allocation could be different.

      Anyway, I think this is a useful conclusion.

  • peterchanwsPeter
    Posted February 25, 2014 at 4:35 am 0Likes

    I have a mid 2010 iMac 3.06 GHz Core i3. I bought a 120 GB Kingston SSD Now and connect it to a spare USB2 case. When I tried to install Mac OS 10.9 to it, it said my drive has problem. My questions are:
    1. Can I use USB interface for my SSD drive. It seems every one either use USB3 or Firewire?
    2. Can I use 120 GB Kingston SSD Now as external boot drive?


    • Robin Monks
      Posted February 27, 2014 at 8:25 pm 0Likes

      Hi Peter! You CANNOT use a USB2 port for this, it’s simply not fast enough and will cause problems. Get a USB 3, Firewire-800 or Thunderbolt enclosure. The drive is adequate for this purpose inside of a proper enclosure.

  • Mark
    Posted March 3, 2014 at 3:52 pm 0Likes

    Hi Guys,

    This looks like a good blog and article so I wondered if anyone can throw any light on an issue I’ve had and been unable to find any definitive info on. I have mid 2010 mac pro and I installed a samsung 500GB ssd in the second drive, I then cloned my hard drive using carbon cloner and set the new ssd as the boot up disc and restarted, all went completely smooth. I was running mountain lion so at that point so thought I’d upgrade to Maverick, big mistake!, downloaded it ok but as soon as it started to install came up with an error saying disc was corrupted and unrepairable which it turned out it was, had to start from scratch and re-clone the hard disc luckily at that point I hadn’t changed anything, but obviously now I’m worried about doing any system upgrades. Did some googling and it seems this problem does occur but there doesn’t seem any clear answers, only thing I can come up with is maybe it’s because the ssd is not in the primary drive? Any thoughts gratefully received.

    • Robin Monks
      Posted March 4, 2014 at 2:40 pm 0Likes

      Probably the best option if you can stand it is to make a install disk and install the new OS cleanly on your SSD. MacOS X does a lot of weird things and when it starts giving you errors like that it’s usually just best to start fresh.

  • Boris
    Posted March 6, 2014 at 12:24 pm 0Likes

    Great write-up Robin! I just ordered a 120GB Lacie Rugged SSD to do the same. Is there any performance benefit in starting with a clean install of OSX Mavericks vs putting back a TimeMachine backup?

  • David Malloch
    Posted March 8, 2014 at 8:47 am 0Likes

    I’m new to Mac having just bought an Imac 27″ with 1Tb drive. I followed the instructions above and added my LaCie 256Gb ok and then booted from it successfully. I did a Time Machine backup and then re-booted using CMD-R but couldn’t see how to selectively restore only the apps I wanted so I cancelled that and copied all the Apps across manually. All seem to have installed OK except Office 2011.

    I cannot see how to get it to re-install on LaCie. I tried downloading the s/w again from Amazon (where I bought it from) so I could run the install from LaCie rather than on the hdd but OS X won’t let me write to LaCie due to insufficient privileges. When I try to download the full install package to the iMac Amazon won’t let me do it because their (re-) installer supports only Windows. Office still works when run from the HDD but I’m losing the speed benefits of the SSD if I continue to run it that way. Advice please.

    • David Malloch
      Posted March 14, 2014 at 9:07 am 0Likes

      I concluded that the only way to solve this was to restore a complete backup so I’ve tried that. So far it’s failed 3 times with the same error – insufficient space on the target drive:

      attempt 1) time machine had backed up everything so I excluded all personal data
      attempt 2) time machine seemed to include any previous backups that had my personal data so I deleted the complete backup file and backed up again from scratch i.e. as far as I was able to I backed up only OS X
      attempt 3) same error

      The backup file is 179Gb and the SSD is 256Gb so what am I doing wrong please ?

  • Jordan Kirkham
    Posted March 12, 2014 at 7:21 pm 0Likes

    Thank you for this post. Running the OS and all programs flawlessly after upgrading to the Lacie Rugged 256GB Thunderbolt. Wish I would have done this a long time ago. Mid 2011 iMac with Mavericks.

  • vic
    Posted March 15, 2014 at 4:02 pm 0Likes

    I was looking for a solution for my problem for 3 hours and I was losing faith but then I saw this article and it worked perfectly. Thanks a LOT for spending time on a great manual 🙂

  • Jeremiah Lowder
    Posted March 28, 2014 at 8:08 am 0Likes

    This is a fantastic article. I have trouble with my late 2012 iMac being sluggish. We bought it right before they came out with the faster drive, so we are stuck. My question is, is there any benefit to usb 3.0 vs thunderbolt? I don’t need to daisy chain, and I saw the issue above about using usb and running windows which I don’t plan on doing. Essentially I just need to boot faster and run adobe creative suite among a few other applications. According to other posts above I would probably need the 256gb model, and thunderbolt is getting pretty pricey. If usb 3.0 is fairly comparable, I would probably just go with that.

    Thanks for putting this article together.

  • NelsonR
    Posted April 1, 2014 at 3:00 pm 0Likes

    I’ve been running a mid 2011 imac with a Samsung SSD 250gig external for 4 months (with a cloned copy on the internal drive) and everything has worked great, until last week. Suddenly my imac won’t let me boot off the external drive. When I hold down option on the restart the drive appears, I choose it, and then it goes ahead and uses the internal drive. The external drive has been verified, repaired by First Aid and I’ve restored a time machine version of it from a few weeks ago as well. The external SSD appears on the desktop, but not in system preferences. Any advice? Thanks in advance…

    • Robin Monks
      Posted April 7, 2014 at 9:04 pm 0Likes

      I’m not sure, I have not seen that occur. My initial thoughts are the system files may have been corrupted somehow, try re-installing Mac OS X on the drive and restoring from a backup.

  • Jake
    Posted April 6, 2014 at 3:20 pm 0Likes

    I have an early 2014 iMac and was going to do the boot drive. Instead, I did DIY fusion. The system doesn’t feel slow, but my Black Magic Benches are not very good (80 & 280). What – in your opinion – are the pros and cons of a ssd boot drive vs. DIY fusion?

    • Robin Monks
      Posted April 7, 2014 at 9:01 pm 0Likes

      SSD will be fast for 100% of the storage space and will never need to slow down to do calculations on where to put files. The downside is it will be smaller/more expensive than a fusion drive. I personally prefer to have a SSD for my OS and Applications and a HDD for my files. That gives me constant speed for my system and plenty of document and file storage.

  • Kemal Dogan
    Posted April 13, 2014 at 3:15 am 0Likes

    G’day Robin, I followed your article and installed Mavericks on a Sagate 240 gb ssd on USB 3. It works perfect, my systems xbench score went up to 326 from 205 with internal hd. While hd scored 76 on xbench, USB 3 ssd scores 426. It is 6 times faster verall. Thanks for your article..

  • Marcel
    Posted April 13, 2014 at 8:07 pm 0Likes

    Hey. Great tutorial. Did it today, but I encountered a problem. I have the Late 2012 iMac and MacBook Air. When I start from my external Samsung 840 EVO 120 GB SSD (connected on USB 3.0 port) using the MacBook Air, everything works fine. But I want to speed up my iMac – and that somehow doesn’t work. When I choose the SSD as startvolume on my iMac (USB 3 as well), it doesn’t load up and just shows up a crossed out circle. Any ideas? Was able to fully boot up on MBA.

  • Joel Arnold
    Posted April 15, 2014 at 1:24 pm 0Likes

    Yes – very nice explanation, very simple and what a huge difference this method makes! I was actually ready to sell my Mid 2011 27″ iMac (2.7Ghz i5, 4GB) due to the slowness at startup and just using iPhoto, iTunes and Safari at the same time. I never realized that the HDD was the bottleneck. I purchased a Lacie reconditioned 128GB SSD for $109 on Lacie’s site. For those who are wondering if purchasing a reconditioned drive is a good idea, I would highly recommend it – they come in standard packaging but are in brand new cases/rubber orange thing and cables – saved over $100 going this route.

    After the install of Maverick’s on the SSD, I copied my iPhoto and iTunes (music) libraries over – still have close to 30GB leftover for apps and whatever else. I couldn’t believe at how fast writing to this disk was, took about 2 minutes to copy over 30GB of music. Also, since the SSD was in a rubber case, all I did was wrap and elastic around the neck of my iMac and secured the SSD to the back – out of sight and working fast.

  • Paul Strauss
    Posted April 19, 2014 at 12:34 am 0Likes

    Worked like a charm! I picked up a 1TB Buffalo DriveStation Mini SSD and my 2011 iMac is FLYING now. Used to take 3 minutes to boot – now less than 10 seconds.

  • David
    Posted April 22, 2014 at 10:07 am 0Likes

    Thank you very much for the instructive guide. Is it possible to run a dual boot (Windows and OSX) setup from the same external SSD? And if yes, do I have to partition it first so it can format in 2 different filesystems for windows and osx?

    • Robin Monks
      Posted May 8, 2014 at 12:12 pm 0Likes

      I’m not sure, i’ve not tried using Bootcamp with an external although I can think of no technical reason why it wouldn’t work. Bootcamp will also handle partitioning for you. An alternative is to have a second SSD for Windows.

  • Yogerson
    Posted May 2, 2014 at 11:00 am 0Likes

    Hi, used to have an external SSD running as my Mac OX 10.9 boot drive. Boot time an app response was second to none; however, my problem was when the computer when to sleep, sometimes the system would become completely unresponsive, I can only assume that the OS was “waking up” before the thunderbird port. Is there a way to fix this??

    • Robin Monks
      Posted May 8, 2014 at 12:16 pm 0Likes

      Check out the Energy Saver preference pane in System Preferences, make sure anything regarding external devices or hard drive going to sleep is disabled. That’s the only place I can think of where such a thing could be controlled. Is the thunderbolt drive powered externally or from the port?

      • Yogerson Falcon
        Posted June 29, 2014 at 6:35 pm 0Likes

        Hi … I already tried disabling the power saving feature.. The enclosure is powered by the port..

  • Natraj Sitaram
    Posted May 3, 2014 at 3:51 pm 0Likes

    Hi I just got a Lacie 500gb SSD drive for my IMAC 2013 and installed mavericks on it successfully . I now have to move my LR5 and Photoshop CC on it ( I am not comfortable using time machine backup method). Do I just copy the programs from my internal HDD and if so will this be considered a third (illegal) installation (the 2 current installation are on my IMAC2013 and MacBook )? Can I use the Lacie as a portable drive and switch between computers to use PS CC and LR5? Thanks for any advise/ tips on best practices before I start….

    • Robin Monks
      Posted May 8, 2014 at 12:18 pm 0Likes

      I doubt you could move CC with that method, it tends to place lots of additional files and resources in the user directory as well as the App folder. I’d recommend uninstalling Creative Cloud and re-installing it in the correct location. In my experience CC will allow you to install as many times as you like, the DRM limitation being that it can only be /running/ from two computers at a time.

  • Yogerson
    Posted May 9, 2014 at 1:31 am 0Likes

    Hi, I did have an thunderbolt external SSD drive running as my boot drive, but I would have problem getting back from the sleep mode. Sometime (most of the time) the Drive would “wake up” after the machine and the OS would become unresponsive. Is there a solution for that??

  • John Kent
    Posted May 14, 2014 at 5:56 am 0Likes

    Hi, I’m about to install the SSD and somewhat confused about the apps. Please confirm that I should plan on uninstalling CS6, Lightroom and other heavily used apps and reinstalling them on the SSD. Will other seldom used apps still work from the internal drive without issue? Thanks for your help.

    • Robin Monks
      Posted May 21, 2014 at 11:06 am 0Likes

      You should installing apps that will benefit on the SSD on the SSD. The rule of thumb should be to have as many of your common apps there as possible. Apps can be moved to the old HDD to save on space, although apps that were already on the HDD before you re-installed may be missing user preferences.

    Posted May 21, 2014 at 10:00 am 0Likes

    I’ve just got a Mac Pro cylinder with internal 256SSD. Upgrade disks PCI-e are not available yet. Can I use an extternal disk as boot/system disk instead of upgrading to a 512SSD PCI-e disk?
    I mean I am completely new to Macs.
    Would it have any penalization in terms of preformance?
    I suppose the option is a thunderbolt disk.
    If so what would be the best use for the internal SSD: second unit for data? Any other use to boost performance?
    I do not need space for data as far as everything is in a NAS GIgabite ethernet connected.

    • Robin Monks
      Posted May 21, 2014 at 11:07 am 0Likes

      You can, and with Thunderbolt the penalty would be minimal.

      • LARdT LARdT
        Posted May 21, 2014 at 11:30 am 0Likes

        Then te SÍ becomes redundant. Any kind of configuration in order to boost performance?
        No need for data storage since everything Will be the NAS.

        • Robin Monks
          Posted May 21, 2014 at 11:37 am 0Likes

          As mentioned elsewhere in these comments, enabling TRIM may improve performance in some situations. Otherwise, there isn’t much you can tweak, it should be fast and stay fast.

  • Pawel
    Posted May 23, 2014 at 7:37 pm 0Likes

    I have a chance to buy a lightly used mac mini with cs6 installed on its hdd drive. Can I somehow move cs6 to the thunderbolt ssd drive and run it from there without reinstalling the app again? I’m moving from pc to mac and would like to use it for lightroom and PS editing, and a mini with software installed looks like good deal. Please let me know. Thank You. Pawel.

    • Robin Monks
      Posted June 6, 2014 at 4:13 pm 0Likes

      Hi Pawel! I don’t have a lot of experience with Lightroom and Photoshop, but I do know that if they follow normal OSX software conventions the settings for the application will be stored in your User folder. That means you can move the app anywhere you like and it should still run without issue. Let us know how it goes!

  • Nick Serr
    Posted May 25, 2014 at 9:44 pm 0Likes

    Hey there, great article, and great that your spend all that time answering questions. I’m about to embark on that project (external ssd with system on). My question relates to back up strategy. I currently create a bootable clone, and use time machine. Will I have to create clones and time machine back ups for both the internal and external drive? Thanks in advance, nick

    • Robin Monks
      Posted June 6, 2014 at 4:12 pm 0Likes

      You can, but only if you want to. Most folks tend to wipe their internal drive and use it as a new device, and then continuing to back it up makes sense, but you can enable/disable the backups on a per-drive basis from within time machine.

      • nick serr
        Posted June 17, 2014 at 3:30 pm 0Likes

        Thanks for the reply. So if I understand well, a back up strategy for this system (external SSD for the system and internal HDD for files) is more complicated. It’s not possible anymore to have just one bootable clone with both system and files, but you need a clone of each. The same applies to Time Machine: TM won’t back up both drives as one, so they have to be back up separately.

        Am I getting it right? And I’m curious to know what your back up strategy for files and system is??

        Thanks again

        • Robin Monks
          Posted June 24, 2014 at 11:46 am 0Likes

          No, TM will back up both drives; and you can have system and files on one drive if you wish.

  • Ellisberg
    Posted May 30, 2014 at 3:17 am 0Likes

    Using a MyDigitalSSD|OTG 256G as my boot disk now. Excellent! This page was the only guide I needed, so thank you very much for posting these instructions, Robin.

  • Polly
    Posted June 4, 2014 at 11:02 pm 0Likes

    Thanks for your article Robin. I read this a while ago when considering booting from an SSD. I now do so from a Lacie Rugged and the pick up in speed is amazing. It ran perfectly for a while but has started rebooting itself because of an ‘error’ 2 or 3 times a day which is becoming a pain. Do you have any ideas why this may be happening?

    • Robin Monks
      Posted June 6, 2014 at 4:11 pm 0Likes

      Hi Polly! It’s possible that the SSD has an error in the disk itself, you can use the Disk Utility tool to check. Open Spotlight and type “Disk Utility”, select the SSD, make sure you’re on the “First Aid”. Click “Verify Disk”.

      If verification fails you might get an option to Repair Disk, which should resolve the issue. If OSX can’t repair the disk you’ll need to contact your SSDs manufacturer for a replacement. Most hard drives carry a 3-5 year 100% coverage warranty.

      If it isn’t the disk, then there is likely an issue elsewhere with your system, posting some additional details of the error message could be helpful.

      • Polly
        Posted June 10, 2014 at 4:45 am 0Likes

        hey thanks for the quick response Robin. I tried the verification but it seemed fine. I ended up digging around and found that the errors can be due to a kernel panic hence a software thing rather than a hardware thing. I switched off all my start up items and it seems to be going ok so far. I’ll switch them on one by one to see if I can isolate the problem. (Just putting that in in-case anyone else has similar issues). Thanks again for your article and time. I haven’t regretted going to external SSD!

  • BPR
    Posted June 9, 2014 at 7:41 pm 0Likes

    Hi Robin,

    I’ve read the article and have been able to guess some details from the extensive comments, but would like to get some clarification on the following scenario: I’m looking to buy a new iMac but have been stumped between the normal (cheaper) HDD ones, or special ordering a Fusion drive. Long story short, it is preferable for me to buy one in store and save the money with an HDD at first. Should I feel constrained by the slower HDD, then if I’m correct, I can simply buy an external SSD Thunderbolt/USB 3 and boot from that (with all apps; primary ones being Photoshop and Lightroom), while still being able to use and access the internal HDD for file storage (and the internal HDD would appear in Finder)? Thanks.

    • Robin Monks
      Posted June 10, 2014 at 1:33 pm 0Likes

      Yep; that’s right! Buying a fusion drive or not is purely a price point thing. Also, fusioon drives will be slightly slower than pure SSDs.

  • blabla
    Posted June 14, 2014 at 12:27 pm 0Likes

    Can you do the blackmagic test (disc read speed) and show me the result?

    • Robin Monks
      Posted June 29, 2014 at 1:23 pm 0Likes

      You’ll see in an earlier comment I provided a screenshot of disk read/write speeds from another utility.

  • Peter
    Posted June 23, 2014 at 1:10 am 0Likes

    Hi Robin, most informative article. Will this work for my late 2009 Mac mini – 2.53 Ghz; Core 2 Duo; 8Gb memory; Mavericks installed and very slow – especially start up.



    • Robin Monks
      Posted June 24, 2014 at 11:49 am 0Likes

      Hi Peter, it will work! Just, you’re limited to a Firewire 800 enclosure (make sure it’s fully 800, and Firewire 400 enclosure won’t be fast enough).

  • Khaled
    Posted June 24, 2014 at 7:52 am 0Likes

    Hi Robin,

    Thanks for the article. Will it work as fast LaCie drives, if I use 128 GB USB 3.0 Flash Drives that are available in the market? (for example: http://www.transcend-info.com/Products/No-610). Thanks

    • Robin Monks
      Posted June 24, 2014 at 11:52 am 0Likes

      These actually aren’t fast enough. The best-case maximum for these is 90MB/s read and 45MB/s write. An actual SSD will have a real-world speed of 320MB/s read and 120MB/s write. So, a real SSD is 3x faster than the flash drives.

  • Gary
    Posted June 24, 2014 at 11:24 pm 0Likes

    Hi all,
    Just a quick question – I’ve been toying with the idea of creating a Fusion drive using my internal 1TB HDD and an external Thunderbolt SSD – an Elgato 120GB Thunderbolt drive, for example.
    I suppose that as long as Disk Utility can see the drives, all is good.
    But I read elsewhere that coreStorage, used to create the logical volume needed in a Fusion drive will only work on internal drives.
    Has the Forum had experience with creating a Fusion drive using an internal 1TB drive and an external Thunderbolt SSD?
    Thanks!! Gary

    • Ken
      Posted May 2, 2015 at 6:06 am 0Likes

      Hi Gary, did you successfully create a fusion drive using your internal HDD and an external Thunderbolt SSD? That’s exactly what I’m pondering doing so was wondering if you had success.

  • Kevin
    Posted June 25, 2014 at 12:34 pm 0Likes

    I cloned my system onto a Crucial 256 gb SSD and have it in an external USB 3 case. I just bought a brand new iMac (most recent generation). If I specify the SSD as my boot drive in System Preferences and restart, it gets hung up and won’t boot. I have to hold option down at startup to get it to start as the SSD. It looks like others have had issues with getting it to boot directly from USB 3. Do you have any solutions?

    • Robin Monks
      Posted June 29, 2014 at 1:19 pm 0Likes

      Hi Kevin, I’ve done a bit of research into why USB3 seems to have issues on Macs. What I’ve taken away from that is this: First, the issue is related to only some enclosures, others will work fine. Secondly, all enclosures should work, and that they don’t is a bug in OSX. Third, Apple has remained very quiet on fixing the bug. If your enclosure doesn’t work properly with OSX your only option is to replace it with another, perhaps with Firewire 800 or Thunderbolt as a connectivity option, which apparently doesn’t have this issue. I’d also highly recommend completing a OSX bug report ( https://www.apple.com/feedback/macosx.html ) to help make compatibility with all enclosures a bigger priority for Apple.

      • Kevin Werther
        Posted June 29, 2014 at 1:59 pm 0Likes

        After finding almost no information on which external cases might work, I did stumble upon someone suggesting the OWC On-The-Go-Pro case. I had been using an Anker case which would not allow me to startup from it. I am happy to report that the OWC case seems to be working via USB 3.0! Hopefully that will continue to hold true. Thanks for everything!

        • Robin Monks
          Posted June 30, 2014 at 11:46 am 0Likes

          Thanks excellent news! Knowing a enclosure that does work out of the box for USB 3 is a great boon. Was this the enclosure you’d found?

          • Kevin Werther
            Posted June 30, 2014 at 12:24 pm 0Likes

            Yes, that is the case! Though, I got it last week through Amazon for $26 I think.

  • Robert
    Posted June 29, 2014 at 2:03 pm 0Likes

    Robin, Thanks for the great blog. I have finally started booting from an SSD and I am very pleased. I am still using the internal drive for the storage of my Home directory and keep it up to date in case of an SSD failure. I also put together a Thunderbolt SSD on the cheap. Instead of buying the Lacie Rugged 250 for $299, I bought the Seagate GoFlex adapter (STAE121) for $85 and a Samsung 840 EVO 250 for $130 and put the two together. I’m not worried about the drive not being enclosed as I can easily swap the SSD in the event of failure or when SSD prices come down and I can upgrade capacity. Besides, even when I heavily tax the drive, it doesn’t get that hot.

    • Robin Monks
      Posted June 30, 2014 at 11:40 am 0Likes

      Awesome! It sounds like you have almost the same setup as me (although I cannibalized a GoFlex HDD case to put the SSD into on mine). Enjoy!

  • David Dolata
    Posted June 29, 2014 at 7:06 pm 0Likes

    Robin, It is very kind of you to be so patient with all these questions. I’ve read everything on this page and am still not certain how to proceed. Many of the comments are admittedly way above my head. My wife has a late 2009 27″ iMac that is making all the noises that many other owners complain about and is slowing down to a crawl. She uses very little storage and mostly surfs. We have Time Machine backups to an older external HD through the iMac’s only Firewire 800 port. I don’t want to worry about a clean system install because I want to make this as simple as can be to limit potential errors, i.e., unless thou think it’s advisable to do so. Since the new external HD must use the port that the existing old external back-up drive currently uses, I’m not sure how to have Time Machine restore her system, apps, and files after creating the partition with Disk Utility as you describe since we cannot connect the old external HD with the TM back-up at the same time as the new external HD. Can we simply have TM back-up to the new external HD since we have room to spare? Or is there another strategy we should employ. Thanks so much for replying to what must seem to you like very basic questions.

    • Robin Monks
      Posted June 30, 2014 at 11:58 am 0Likes

      Does either drive have a USB connectivity option? If so, it’ll be slower during setup but you can use one in USB mode to complete the directions.

      • David Dolata
        Posted June 30, 2014 at 12:28 pm 0Likes

        The backup HD has one extra Firewire 800 port, but the new HD that I want to use includes USB 2, which is what the iMac has. So, set up the new HD with the USB 2, realizing that it’ll be a slow process, followed by restoration of back-up by Firewire 800, and after that is all done, disconnect the old backup HD and use the Firewire 800 for the new external HD?

        • Robin Monks
          Posted June 30, 2014 at 1:48 pm 0Likes

          If the Backup HDD has 2 firewire ports it might be made to be “daisy-chained” to another drive. Trying plugging one into your Mac and the other into your second drive and see if both spin up. Otherwise, yes, do the process as you described.

  • prenez
    Posted July 14, 2014 at 10:35 am 0Likes

    I’ve had a lot of success using an AngelBird 512gb SSD2GO drive, it’s kinda the RollsRoyce solution, but I have a mid 2010 iMac with USB 2.0. Love it–WAY faster than my internal HDD.

    PocketVault, on the other hand, has been a disaster, and just ate up about three days of my time. Slow to begin with, I am getting endless disk accesses and, for the life of me, can’t figure out why. I dragged every folder I had to Privacy in Spotlight, so I doubt it’s that.

  • Jason
    Posted July 16, 2014 at 2:26 am 0Likes

    Thanks for posting the detailed instructions. Used them to set up a LaCie 120GB SSD on my 2013 iMac and the performance difference is amazing! I am having some trouble though. I wasn’t able to restore from a time machine backup because the backup was larger than my new SSD. So I’m essentially setting it up from scratch, which is a pain. I really just want the most common programs to run on SSD and use the internal HD for storage. I can’t seem to get MS Office to move over. When I copy from the internal HD to the SSD and try to run, I get an error. Any ideas how I can migrate MS office over? I also can’t seem to run office from the internal HD when booted from the SSD (same error). I appreciate any help you can offer!

    • Robin Monks
      Posted July 27, 2014 at 6:04 pm 0Likes

      Your best bet, if you can, might be to install the trial version of MS Office and activate it using your existing key. Hope that helps!

      • Jason
        Posted July 28, 2014 at 12:09 am 0Likes

        Thanks! I was able to get Office up and running from the SSD.

  • Adam
    Posted July 27, 2014 at 3:55 pm 0Likes

    Thank you for posting this write up. I am not a computer expert by any stretch and was able to do this conversion on my mid-2011 21.5″ iMac with no problems. I got a 256Gb Lacie SSD for $250 and did a clean install of Mavericks. The SSD is connected to the Thunderbolt port. Now I’m using my 500Gb spindle drive as media storage. Everything starts up much faster and no more beach balls!

    • Adam
      Posted August 10, 2014 at 4:46 pm 0Likes

      Well I may have spoken too soon. I shut the iMac down for a week while on vacation. When I came back it kept crashing and had the “Invalid node structure” error when I did verify disk in disk utilities. I’m trying to re-install on the internal drive and get it back running again. Not sure what happened…

      • Robin Monks
        Posted September 4, 2014 at 3:38 pm 0Likes

        If you’re getting that error there’s a high chance the SSD is bad. Calling the manufacturer should yield a free replacement, and if it’s been less than 30 days the store you bought it from can also exchange it.

  • Richard Macgurn
    Posted August 7, 2014 at 12:01 am 0Likes

    first let me say thanks Robin for this article as i was going to do the fusion thing but decide was more logical to put all the OS and programs on the SSD using the internet 1TB for data (except for outlook 2011 which had to go on the SSD also); suing a 256mb Samsung and the seagate thunderbolt adapter.

    Ran great for about a week then a very odd thing started as i use safari mostly with 3-4 windows and 8-10 tabs each window, i thought i had internet issues, changed the modem the airport express tried using direct connect and nothing fixed it. the issue is with more then 3 or 4 tabs open safari quits loading any thing, so does firefox and chrome. Mail outlook keep going but even the app store stops. i tried all the fixes i could find even safe mode then by accident i discovered that if i boot on the old internal drive its fine, can have lots of tabs and it loads very fast. Tried to erase the safari cache, and some plist files but nothing seems to fix it except going back to the old drive to boot. hate to go the fusion set up as i am sure it will be much slower as i use autocad and trade stocks too, so always have a lot open and use 16gb of mem. about 100%. cant seem to figure what this could be and i am sure wondering why it took a week to get this way, seems like a file overflow or cache issue but damn if i can find it and it also effect many programs that bring data in from the net now just safari.

    ill run a few days on the old internal disk hoping someone might have had this same problem and fixed it???

    thanks in advance


    • Robin Monks
      Posted September 4, 2014 at 3:40 pm 0Likes

      That’s a very weird issue! It sounds like something is wrong with your cache or connection. I’ve never seen anything like that, hopefully someone else has and can offer some advice!

  • Slava
    Posted August 15, 2014 at 6:49 pm 0Likes

    Hi Robin, I have a imac 21.5 mid 2010 , internal hdd 500gb/7200
    In this imac internal sata 2 , USB 2 and FireWire 800
    A Mac as very slowly , I want to install SSD
    What you think about install internal SSD with optibay or external FW 800 ???
    Generally If this upgrade it standing for me ?
    Sorry about my English …

    • Robin Monks
      Posted September 4, 2014 at 3:38 pm 0Likes

      In that sort of setup the Firewire 800 is likely your best option.

  • Gavin Macfie
    Posted August 27, 2014 at 7:44 pm 0Likes

    Thanks for the post. I just upgraded my Macbook Air SSD to a Transcend Jetdrive 520. The kit came with a kit to mount the Air SSD into a USB 3.0 housing. I was planning to follow your advice and use it to boot my iMac. Unfortunately the iMac has USB 2.0 ports.

    Are you aware of any way I could connect the Air SSD to thunderbolt?


    • Robin Monks
      Posted September 4, 2014 at 3:36 pm 0Likes

      From reading your comment I believe you’ll be booking from the Transcend internally. If you’re just using the old mounted drive for storage you can probably get away with USB 2.0 without any issues.

  • Nelson Domingues
    Posted September 2, 2014 at 8:05 am 0Likes

    Hello, I’m needing some help with my “new” iMac.
    I got a samsung 840 evo with 120 gb and connect it through the thunderbolt port i my mid 2011 iMac.
    Then after a re-start and, I got the system “recovered” to the new drive. Then I erased my iMac internal hard drive.
    Now I Want to move some of my folders like Documents and Downloads to the internal drive. To do that using symlinks I need to delete first those directories, after of course copying them from the boot drive (ssd) to the internal HD. I tried it using the command line: sudo rm -rf ~/Documents, but after entering the password, asked next to entering the command, nothing happened to the Documents folder.
    And without deleting the folder first I can’t create the symlink.

    Can you understand why I not being able to delete de download?
    Curiously I managed to do just that in a previously installation, in witch I’ve done a clean install of mavericks in the new drive…

    Please share your thoughts about this.

    • Robin Monks
      Posted September 4, 2014 at 3:42 pm 0Likes

      I suspect those are magic folders that are hard coded into the OS. After some looking at various support communities, the generally consensus is if you want to move those data folders you should move your whole user directory to the other drive (which OSX supports natively!) I think you’ll find these instructions will help.

    • Robin Monks
      Posted September 4, 2014 at 3:34 pm 0Likes

      That’s very neat! It should work as a boot device too, although the initial investment (from looking at the product on Amazon) is quite a bit higher. $500-600 for 4GB, which is a lot more space and cheaper per GB, but, a bit more of an investment. Let us know if you use one of these with your Mac what your results are!

  • Tracey
    Posted October 3, 2014 at 4:37 pm 0Likes

    Thanks Richard for putting this together. I have used carbon copy to take a full backup of my hardrive. Plan is to install the OSX onto the SSD only have a 64gb, and use the hardrive inside the Mac mini for storage. New to doing this, so do I wipe the internal HDD after ensuring it boots from the SSD and then just copy over the files I need? or can you keep the internal drive as is and just use files from it when needed?

    • Robin Monks
      Posted October 8, 2014 at 5:11 pm 0Likes

      You can do it either way, although you won’t get the full available space until you format the internal drive.

  • Don
    Posted November 11, 2014 at 8:59 pm 0Likes

    Hello Robin. Thanks for the great article and all your answered questions. I have a 2007 imac (2.0GHz Intel Core 2 Duo, 4G of ram, a 250 G 7200rpm hard drive, and one FireWire 800 port 7 watts). I know my computer is old but it still does the job. I would like to gain some speed and some extra memory by adding a (Crucial MX100 512GB SATA 2.5 CT512MX100SSD1) and a (Mercury Elite Pro mini 2.5″ Portable FW800/400 + USB3.0 portable SATA 2.5″ Drive Enclosure Kit). I would connect this using the provided firewire 800 ports and cable. I have read all the comments above and have yet to read of anyone doing an external boot on a machine as old as mine. So my question is do you think your procedure would work on my machine and would I still see a great increase in speed even thou I am using firewire 800. Thanks.

    • Robin Monks
      Posted November 12, 2014 at 7:49 pm 0Likes

      Hi Don,

      Sadly I honestly can’t tell you, I don’t have a machine that old for testing. My best advice would be to get the external drive from a local store you can return it to if it doesn’t work. Either way, let us know the result!

  • Sebastian Gorski
    Posted November 16, 2014 at 4:20 pm 0Likes


    Will this also work for a portable ssd drive like this:

    Or do you actually need to have a power source like an external ssd has?


    • Stella
      Posted November 18, 2014 at 10:47 pm 0Likes

      Thanks to Robin I now boot from a Lacie Rugged which is bus powered so I’m guessing that this one should be fine.

    • Robin Monks
      Posted November 19, 2014 at 7:03 pm 0Likes

      Hi Sebastian, it shouldn’t matter if the drive is self-powered or powered externally.

  • Ioannis
    Posted November 20, 2014 at 2:28 pm 0Likes

    Hello Robin!Great Article!
    Are you familiar with the issues that arise after OS Yosemite?Regarding this party SSD’s and trim?
    Serious issue and unfortunately i got a new samsung evo 500gb thought i should put it as internal but now seeing many people that say apple won’t support trim for third party manufacturer
    so if i use this as an external via usb..what will happen to trim?i think trim is quite important for the speed and health of the drive

    whats your views?

    • Robin Monks
      Posted November 22, 2014 at 11:30 pm 0Likes

      Hi there,

      I’ve answered some of this before (way up there in the comments, search for TRIM on this page 😉 ). First and foremost, most drives no longer need TRIM to the extent they used to. See a page on TRIM for Crucial SSDs here, for instance. So, in 9 out of 10 cases TRIM is not going to affect your experience. Doing a brief bit of google searching will tell you if your SSD has firmware to keep the drive happy without TRIM (your Evo, for instance, does automatic garbage collection). Almost any modern drive is going to have it.

      If you have a drive that DOES require TRIM, follow the guide here and ESPECIALLY print off the “Recovering from stop sign on boot screen” section and store it with your computer.

      • Ioannis
        Posted November 23, 2014 at 11:43 am 0Likes

        So my Evo would be ok if i leave 10 per cent of the drive’s capacity for garbage collection right?
        the problem that i saw is that samsung issued an update for the EVo sad’s since many users complained about speed performance…so before i use the drive as external i have to place it internal to do the upgrade on firmware since i can’t through usb 3 (this if from samsung documentation)

        a bit of a time consuming process since the mac mini 2012 comes with only one data cable have to place new drive..install os …then update and the take the drive out and place it as external 🙁

        • Robin Monks
          Posted November 24, 2014 at 12:36 pm 0Likes

          Ouch, firmware updates can be a bit of a pain regardless of platform. Ultimately though, yes, your drive should be fine with working garbage collection.

  • Danny T
    Posted November 22, 2014 at 9:13 pm 0Likes

    Hi Robin,

    Great guide, hoping to get the LaCie SSD soon just a couple of questions though.

    Can I start fresh on the SSD and install my apps to it then have them read my old libraries on the HDD (left intact, not erased, therefore still running OS X)? For example Aperture, my photo library is quite large and would take up a lot of valuable space on the SSD. Can I leave my Aperture library on the HDD and have it read by Aperture on the SSD?

    Also will I need to boot into my HDD when there is an OS X update to keep things running smoothly?

    Or would it just be best to have the HDD erased and copy files back to it?


    • Robin Monks
      Posted November 22, 2014 at 11:32 pm 0Likes

      Hey Danny! You don’t need to keep a second copy of OS X to store your libraries on your HDD. Libraries are just folders that OS X prevents you from looking inside of yourself easily. Thankfully, there’s a simple guide here that shows you how to move them wherever you’d like.

      • Danny T
        Posted November 23, 2014 at 11:06 am 0Likes

        Thanks Robin! I’ll look into it, hopefully I will be living a faster life soon!

  • Adam
    Posted November 30, 2014 at 9:08 pm 0Likes

    Hi Robin, excellent article
    Am new to things like this but does the ssd and the hdd work together for example if I had a 120 gb ssd and 1tb of internal storage on my imac would it have a total of 1.12 tb like a fusion drive or would they work as two separate drives and means you have to restart your imac each time you want to switch from the lower capacity ssd to the 1 tb internal hdd.
    I may be sounding a bit dumb. Dont know how it works exactly yet

    • Robin Monks
      Posted December 12, 2014 at 1:54 pm 0Likes

      Hey Adam! It’s not a dumb question at all. The drives will be separate, but, you can still access the large 1TB HDD while running your OS on the smaller SSD. Then you can have your computer boot and run fast because the OS is on the SSD and you can keep all your files on the more spacious HDD. Hope that explains it for ya!

      • ADAM
        Posted December 22, 2014 at 1:54 pm 0Likes

        Thats excellent robin thanks very much

  • Stephen
    Posted December 11, 2014 at 10:24 am 0Likes

    Hi Robin, really interesting post and great to see you are still answering people’s questions 🙂 I have one and I’d be very grateful for your views. I want to use an external SSD at work with a thunderbolt equipped MBP. However, when I get home I want to plug the SSD into my Mid 2010 imac, which only has firewire 800. I can’t seem to find an SSD that will connect to both, and I don’t think Apple’s Thunderbolt to Firewire cable will be suitable for this purpose. Do you have any ideas? Thanks!

    • Robin Monks
      Posted December 12, 2014 at 1:52 pm 0Likes

      The Thunderbolt to Firewire 800 adapter should actually be what you try first. It’s dicey for some drives, but works for the majority and if it works for yours you’ll be good to go for $30. If it doesn’t work, you can easily return it. The alternative is a shoe like this one where you can buy a shoe for Thunderbolt (or USB 3 which if on your MBP is likely going to be much cheaper for you) and another for Firewire 800.

  • Jeremiah
    Posted December 11, 2014 at 11:50 pm 0Likes

    Hi there,

    I followed your instructions several months ago and installed my OS on a 128gb LaCie thunderbolt ssd to use with my iMac. I was so happy with the performance boost.

    Then when I upgraded to Yosemite, I started noticing performance issues, slow start ups etc.

    So I did a fresh install of everything. I use the internal iMac drive as a storage drive and boot from the ssd. Now, it is so bad, it is essentially unusable. Opening an app like safari causes the spinning beach ball. If I hit “shut down” it takes up to 10 minutes to complete the shut down process.

    Any advice? I have looked into TRIM but I read your responses indicating this is not as much of an issue anymore.

    Thank you.


    • Robin Monks
      Posted December 12, 2014 at 1:45 pm 0Likes

      That’s quite interesting. A few things to check:

      1. Make sure you’re still connected via USB 3/Thunderbolt or Firewire 800
      2. Make sure the new install of OS X installed to the right disc and didn’t get put back onto the HDD for some reason
      3. plug the disc into another computer and check if the disc is performing badly there as well (if this is the case, the disk may be failing and can be replaced by the manufacturer, chances are for free if it’s less than 3 years old).
  • Justin Van Tol
    Posted December 13, 2014 at 10:18 am 0Likes

    Hi Robin,

    Is your setup still doing fine?

    I have an iMac late 2012, and i’m about to buy an Lacie External SSD and use te same setup.

    I’m curious about the fact that it is an external drive. It scares me that it will maybe not last as long as an internal SSD.



    • Robin Monks
      Posted December 14, 2014 at 1:56 pm 0Likes

      I use it daily as my work computer, and it’s run perfectly since install (though a few OS X versions too). So far I’ve had no durability or stability problems.

  • Richard Macgurn
    Posted December 13, 2014 at 2:40 pm 0Likes

    i followed you guide and added an external EVO 64BG for the OS can use the internal 1TB for data, music, fotos, DWGs etc. all programs are installed on the SSD and the OS. it was doing very well until Yosemite. then a spotlight issues started. constantly crashing. on the apple boards many reported the same whenever there was an external drive and suggested i eliminate the indexing of the external drives (that inc;used my time machine USB3 2TB external drive. my Imac 27 is late 2013 with 3,2GB fire i5 and 16gb memory. I have added the SSD, the spotlight drive and about 1/2 of my internal 1TB drive to privacy list of spotlight trying to see what might be causing the crash of spotlight saying Error: unexpected indexing state. kMDConfigSearchLevelTransitioning’ or ‘Error: Index is already changing state. Please try again in a moment.’,

    • Robin Monks
      Posted December 14, 2014 at 2:02 pm 0Likes

      I run Yosemite with my setup and haven’t experienced issues, both drives are also indexed. From what I understand you’re using an SD card as the “external” drive, right? I’d suggest removing any other drives except your SSH and HDD and seeing if the problem continues to rule out your time machine drive. If it continues, you may need to re-install OS X from scratch.

  • Richard Macgurn
    Posted December 13, 2014 at 2:41 pm 0Likes

    the only way i can fix it is to follow this bloghttp://www.sciencemedianetwork.org/Blog/20130321_Spotlight_fix which unloads and reloads spotlight drivers. then maybe a day or 3 same thing occurs. now they suggest i go back to using just the internal drive for all. NO WAY. not going back to windows machine either. one more thing i idid a full wipe and reinstall the OS and programs from scratch on the SSD just to be sure and same thing again. whats weird is it seems to be hitting the problem on the internal drive. and I’ve ran all the disk utilities to repair that drive to no avail says no problems.

    thoughts ideas or others with this problem??



    • Robin Monks
      Posted December 14, 2014 at 2:03 pm 0Likes

      You might consider install Yosemite on the HDD and then if it continues taking it to the Apple Stoe for repair (if it’s under warranty). If the issue persists with all original hardware you can get at least the hard drive replaced.

  • Francesco
    Posted December 13, 2014 at 6:21 pm 0Likes

    Hello to everyone,
    I have an iMac late 2006, with FW and USB2. do you think I can get better performace, using a SSD to boot it ?

    • Robin Monks
      Posted December 14, 2014 at 1:55 pm 0Likes

      Only the 24 inch model in that year supports Firewire 800; if you have a smaller size iMac you won’t see a performance benefit.

  • James
    Posted December 18, 2014 at 3:23 am 0Likes

    After setting up an iMac my sister, brother in law and I went in on for my nephew I was underwhelmed by the speed of the 5400rpm in the stock top tier 21.5inch iMac. I searched the web and wasn’t sure I wanted to give this a shot till I read your walkthrough that made it look really easy. And it was, 2 hours of my time and about $120. The system now runs like it should.

    First time ever using OS X and now I want this system! installed Minecraft and a Christmas mod (also a first for me). Then built a little christmas house with a train and the works. He is going to flip out!


    • Robin Monks
      Posted December 18, 2014 at 1:34 pm 0Likes

      Glad to hear it! Merry Christmas!

    • Rodrigo Jorge Gutierrez
      Posted January 9, 2015 at 2:22 pm 0Likes

      What did you find for only $120? I want to add an external SSD boot drive to my 2011 iMac but the Lacie and Buffalo options are typically at least $170.

  • ari
    Posted December 28, 2014 at 5:46 am 0Likes

    Hi Robin, I hit a snag in the process. I partitioned my new ssd and download Maverick again, no problems. I continued with the install wizard and was never offered a chance to load the OS on the new drive. I continued to hope for that opportunity but…. Oh, no, the darn thing installed Itself on my iMac where I am already running 10.9. So now I have to recover from that and try again. How can I get the OS to install on the SSD?

    • Robin Monks
      Posted December 28, 2014 at 8:50 pm 0Likes

      You’ll need to run the install from outside of the existing installation. Making an install USB is likely the best option to accomplish that. From there you’ll be given the option.

  • Rishio
    Posted January 14, 2015 at 7:10 pm 0Likes

    Hey Robin,

    My MacBook Pro 2011 Motherboard tried. Since I can’t afford a new/fast computer at this time, my plan is to:

    1. remove the 750 gb hard disk from the macbook
    2. put it in an enclosure
    3. buy a 500gb usb 3 ssd
    4. Connect both hard drive and a third time machined one to a computer at the Apple Store
    5. Restart the mac to boot from my old hard drive

    Here is where the question comes in:

    Do I carbon copy the old hard drive to the new one or do I use my third time machine hard drive and do a clean install on my ssd and use time machine to get my old stuff back? Is there an advantage to use the time machine method versus the carbon copy method?

    Once complete, my plan is to use friends/Apple Store computers to boot from my ssd and work with different machines.

    Is my entire plan a workable one? It seems complex. Do you have a simpler idea how to get my OS X onto the ssd given my situation? I’d imagine I’d have to be at the Apple Store messing with their computer the whole day to get this to work.

    Thanks if you can help!

    • Robin Monks
      Posted January 14, 2015 at 7:28 pm 0Likes

      Wow… that’s quite a plan! Honestly, I’ve not tried anything like that so I couldn’t tell you what will happen or if it’ll work. What I can ask, is please let us know how it turns out!

      • rishio
        Posted January 17, 2015 at 8:39 pm 0Likes

        I went ahead with it. Loaded the latest Mac OS X on a 500gb usb 3 ssd. Have been running in on my girl-friends macbook air at home and a Mac Pro at the apple store with no problem. It’s pretty amazing – no matter where I travel, I can carry the soul of my computer in my pocket and plug it into any modern mac. I no longer have to spend on average a $1000 a year on a fancy mac to do my video and photography editing.. The pocket Mac combined with my LTE iPad seem great for my lifestyle..

  • James
    Posted January 18, 2015 at 3:47 pm 0Likes

    excellent article! I am in the process of setting up. I just installed my SSD in my external enclosure and I am downloading full installer to my internal HD as I type. I have one quick question so far, I assume I need to format my external SSD before proceeding with your first step above “Open the Disk Utility (command+space and type the name of the application) and click on your NEW external SSD and choose the Partition tab, and choose 1 Partition from the drop-down menu. Select Mac OS Extended (Journaled) as the Format and Name the new partition whatever you’d like.”

    • Robin Monks
      Posted January 22, 2015 at 11:16 pm 0Likes

      You may, depending entirely on how the drive is formatted by the manufacturer. I didn’t, but if you find you can’t create the partition formatting will fix the issue.

  • James
    Posted January 22, 2015 at 9:42 pm 0Likes

    hello, excellent article. I went ahead and setup an external SSD. What is the best way to delete the old OS files, boot up etc.. on the internal drive?

    • Robin Monks
      Posted January 22, 2015 at 11:15 pm 0Likes

      If you no longer need them, formatting the internal drive is the best option.

  • Dave
    Posted January 23, 2015 at 1:47 pm 0Likes

    Great article, I am about to go down the same route of using a external SSD as a system drive. What I wanted to know, if I format the internal drive so that I can use it for data. Is the recovery partition available for future use if I want to use it again?

    • Robin Monks
      Posted January 23, 2015 at 1:54 pm 0Likes

      OSX will store recover files on the startup drive when you install OSX, so the recovery partition will be re-made on your SSD. Additionally, if you have any of the following models or newer internet-based recovery is possible without a recovery partition:

      • MacBook Pro (13-inch, Early 2011)
      • MacBook Pro (15-inch, Early 2011)
      • MacBook Pro (17-inch, Early 2011)
      • iMac (21.5-inch, Mid 2011)
      • iMac (27-inch, Mid 2011)
      • MacBook (13-inch, Mid 2010)
      • MacBook Pro (13-inch, Mid 2010)
      • Mac mini (Mid 2010)
      • MacBook Pro (15-inch and 17-inch, Mid 2010)
      • iMac (21.5-inch and 27-inch, Mid 2010)
      • MacBook Air (11-inch and 13-inch, Late 2010)
      • Dave
        Posted January 23, 2015 at 2:00 pm 0Likes

        Thanks Robin for your reply, my current model is 27in iMac late 2013. This weekends project is up-grading to a external SSD Lacie 256gb thunderbolt drive.

  • Richard Macgurn
    Posted January 31, 2015 at 11:24 pm 0Likes

    anyone else notice after the upgrade to 10.2.2 the internet is very slow again. but even stranger is the amount mac shows 10.2 only but in the full system report are listed the 10.2.1 and10.2.2 updates. is that normal or something to do with the external SSD thing?

    • Richard Macgurn
      Posted January 31, 2015 at 11:25 pm 0Likes

      about mac sorry.

  • Tom Breen
    Posted February 1, 2015 at 1:57 pm 0Likes

    i have OS X boot up on an ssd ,now just 2 stupid questions i know
    1 do erase my internal hdd and have it as storage and how do set that up???

  • Robert Mellor
    Posted February 2, 2015 at 11:21 pm 0Likes

    Robin, thank you for this article. I already sent away to OWS for a SSD and their special upgrade kit so that I could try and install the new SSD behind the optical drive in my 2011 27 inch iMac and make it my boot disc then I found your article – finally a use for my thunderbolt port! And no need to to dis-assemble my Mac.

    But…I don’t yet have an enclosure or thunderbolt cable for the SSD which will now be external rather than internal. All I can find online are complete kits with HDD or SSD I don’t need. Can you suggest a cheaper
    Kind regards and thanks again for this article

  • Lee
    Posted February 9, 2015 at 1:57 pm 0Likes

    I finally got round to adding a LaCie SSD Thunderbolt 550Gb drive to my Mid 2011 iMac 27″after reading this article months ago. I am still finding that when I do anything on the SSD drive the internal drive spins up which is annoying. Is there anything I can do to stop this? otherwise I am finding everything much snappier. It took a while to sort the software out and I have managed to get keep my large itunes movie library on the internal drive and my iPhoto library but surely this shouldn’t cause the drive to spin when I just go to search in Alfred for nothing related to either of those libraries?

  • Stephen
    Posted February 9, 2015 at 5:21 pm 0Likes

    I previously followed these instructions to set up an external SSD boot drive on a 2012 Mac Mini, and it worked great. Recently, I did the same after purchasing the bottom-of-the-range 2014 Mac Mini (the one with a Macbook Air processor and just 4GB RAM). I thought I was being really smart, to get such a cheap Mac which would run blazing-fast (based on my experience with the 2012 Mini).

    At first, it was a disaster. The Mac was slow, slow, slow when booting from the external Thunderbolt SSD. It would choke on just about anything – opening an app, playing a video in iTunes, opening a website which had Flash elements. I was feeling pretty chastened, at this point, until I read that the problem may be caused by OS X Yosemite disabling support for TRIM on third-party SSDs.

    So I installed a free app called Chameleon SSD Optimiser, which bypasses Apple’s restrictions and enables TRIM – and eureka, my bottom-of-the-range Mac Mini is now flying, This £399 computer now works as fast, in general computing tasks, as my MacBook Pro. So, I’m leaving this comment here in case it helps anyone who finds themselves with a slow computer after following these instructions and installing Yosemite on an external SSD. Download Chameleon SSD Optimiser (or similar) and you’ll probably be back in business.

    • Stella
      Posted February 10, 2015 at 8:09 am 0Likes

      This is great information. The TRIM problem has stopped me from upgrading to Yosemite. Thanks Stephen

    • Stella
      Posted February 10, 2015 at 8:20 am 0Likes

      …I may have spoken too soon. From a quick hunt around it looks like Chameleon works by disabling Apple’s kext signing? I didn’t want to do that for security reasons. Do you know if this is true?

      • Stephen
        Posted February 10, 2015 at 8:42 am 0Likes

        Yes, this is the trade-off. You have to disable the new Kext signing restrictions which Apple introduced in Yosemite. If you do it, you should be sure that you only install system drivers which you trust. I’m comfortable with this, because there’s very little I install on a Mac (other than a few apps from the Mac App Store). Plus, my computer was literally unusable before I did this. But if you often install system drivers from various sources, it’s probably a more complex choice.

        It’s also worth noting that this may not be a long-term fix. Apple may implement OS X upgrades which prevent this workaround in the future. I plan to buy a new, compatible SSD at some point, which won’t require this TRIM hack (apparently there are some). So for me, this is a temporary repair until I have the time to set up a new SSD boot drive.

        PS: I also read somewhere that you only need to enable TRIM temporarily, to get the SSD up to full speed again (i.e. to make the drive understand that it’s not full). So in theory, you could then re-enable the kext signing restrictions until you experience a slowdown. And with a new SSD, it probably wouldn’t even be an issue for a while. I haven’t tested any of this, though (mine was an old SSD, previously used with another computer). If you start off with a new SSD which doesn’t require TRIM, then I suspect none of this is necessary.

        • Stella
          Posted February 10, 2015 at 10:48 pm 0Likes

          Again thanks for the great info Stephen. I was hoping that Chameleon solved both TRIM and kext issues. In that case I will probably stick with Trim Enabler that I already have. It does the same thing as Chameleon only its meant to be a little safer in avoiding grey boot ups. I too noticed bad SSD performance issues and Trim Enabler sorted that out swiftly so I do believe that TRIM support is important. I had a quick look around to see if there were any Apple supported external SSD drives but I didn’t find any. Let me know if you come across one.

  • cdawg
    Posted February 26, 2015 at 4:31 am 0Likes

    hi… read all this. Brilliant, works great. I have one issue. Software update isn’t working. Any suggestions?

  • Danny T
    Posted March 1, 2015 at 12:03 am 0Likes

    Hi Robin,

    Finally doing this soon, just waiting for an enclosure from Amazon 🙁 I just wondered if you’d had any experiences with thunderbolt firmware updates. Does it affect connectivity at all as it updates?

  • edinsb
    Posted March 29, 2015 at 6:39 pm 0Likes

    Robin, great article. I have set up a external thunderbird ssd drive running yosemite but i keep running into an issue that my files and apps on my internal hard drive are locked. The ssd isn’t large enough to copy all of the hdd over to the ssd. You dont seem to have this problem. The hdd is running mavericks not yosemite and is still bootable. Any help would be appreciated.

    • Robin Monks
      Posted March 30, 2015 at 4:20 am 0Likes

      If they are “locked” it sounds to be that the user permissions are set incorrectly on those files. I (like most people) continued to use the internal drive for storage so moving all files onto the SSD wasn’t necessary. This apple support article (specifically the How to View and Change Permissions in the Finder’s Info Window section, should be able to guide you on how to unlock those files.

  • dimosd1
    Posted April 23, 2015 at 12:01 am 0Likes

    Hello. Great article, Robin. I’m sure you’ve helped more people than you can imagine!

    I read your article several months ago and the idea of speeding up my mid 2011 iMac with an external boot SSD suddenly became very appealing. To tell you the truth I was unsure about the outcome. Would it make more sense to get a new iMac with a fusion drive? SSD drives don’t come cheap after all. A few days ago, I finally decided to go ahead with the SSD option. If things didn’t work out as planned, I could still use it for fast external storage. Well, now that I’ve got everything set up, I’m definetly not getting a new iMac this year! My system now boots in 15 seconds (from 1 min. 10 seconds) and apps are really fast. My iMac was never slow but now it’s like a new machine! The only problem I encountered was that the system would become unresponsive when waking from sleep. After some research, I found out this is a common issue with many ssd’s and your advice to deactivate sleep mode was the only effective solution. In my case, I had to deactivate both computer and hard disk sleep to resolve the issue.

    The method I used was a bit different. My internal hdd had almost 600GB of data on it, system and user files. The ssd I got was a Lacie Rugged Thunderbolt 500GB, so I opted to Carbon Copy Clone only my system files to the ssd and keep the home folder in the internal hdd. My question is if I decide to delete the original system files on the hdd, do I just move the three folders (Aplications, Library and System) to the Trash and leave the Users folder intact?

    Thank you so much for a very informative article.

  • Jan
    Posted May 9, 2015 at 8:12 am 0Likes

    Hello Robin,
    Thanks to your article I’ve added an external Transcend Thunderbolt TS256GSJM500 SSD drive to my iMac 2011. I use this drive as boot drive, and it really speeded up my iMac!
    However ……….. there is one strange thing that occurs.
    As I’m travelling during the week, I only use my imagine the weekends.
    When I start my iMac after a week, he doesn’t boot from SSD drive, but it goes to the disk utility screen. There I can choose the SSD as boot drive (there is no there boot drive).
    This only happens when I do not use the iMac during several days.
    When I start my iMac each day, I do not have this issue.
    Are you familiar with this behavior, and do you have a workaround?

  • Angus
    Posted May 21, 2015 at 6:04 pm 0Likes

    Great article. I am planning to get an external SSD for my 27″ iMac mid-2011. Should I leave all the applications and files in the old internal HDD? I normally use FCPX for video editing. How is the performance between external OS and internal App? Is it better than my current setting (OS and App in internal HDD). I don’t mind that much for the booting time, I only concern the working performance. Thank you very much for your advice!!!

    • Dave
      Posted August 9, 2015 at 6:34 pm 0Likes

      Angus, I just did the exact thing on a 2011 27″ iMac with a 120GB ssd external two days ago. I’m already seeing a HUGE improvement in application speed. I don’t use FCP, but I do use iMovie and Aperture. The speed pickup is tremendous. Even iTunes deals with my big library better. I HIGHLY recommend moving the applications over. Use the internal for file storage.

    • Natraj
      Posted December 31, 2015 at 8:43 pm 0Likes

      Hi Angus: I got a 500gb lacie external SSD drive for my imac 2011. Moved all my applications (including photoshop and lightroom) plus OS El capitan to the external drive. Hooked up another 2Tb (non-ssd) external drive to hold all my photographs (which occupies almost 1Tb). I use the internal HDD of my imac only for for my lightrooom master catalogue and preview files (about 40GB). I am able to start lightroom in 7 secs and photoshop in 27 secs. Big difference!

  • tom
    Posted July 16, 2015 at 4:22 pm 0Likes

    Thanks for the tutorial! Speed is like on a new computer now! No problems! Only 222 euros instead of 2300 euros for a new iMac! Great investment!

    Thanks again

  • Dave
    Posted August 9, 2015 at 6:32 pm 0Likes

    This is fantastic. $150 and an hour to turn a 4 year-old-iMac into a new machine. THANK YOU!

  • Daniele
    Posted August 26, 2015 at 3:33 pm 0Likes

    Hi Robin,
    after reading your excellent article and the zillions of positive feedbacks I am tempted to rework my MacBookPro (Late 2011). As my plan is a little different from what I have read so far I’m not sure whether this will work out OK.
    I’d like to hook-up a SATA-SSD (Samsung 850) externally via a Delock-Converter (Thunderbolt to SATA) and set-up Yosemite while (for the moment) preserving the internal drive (OS X 10.7.5 with Parallels and Bootcamp). So I will be able to set-up my new SSD the way I want, keeping the possibility to work with my old environment anytime I need to just by booting from the old drive.
    Do you know whether the Delock-Converter allows for booting from the external SSD drive?
    Assuming it is possible, will I be able one day to just swap the SDD and the old drive and use the newly created SSD in place of the old one?

    Thanks for your thoughts on this

  • Sean
    Posted October 13, 2015 at 1:47 pm 0Likes

    I also just tried this set up on a Mac mini mid 2011. Through a thunderbolt connection, I’m running El Capitan on an external SSD and the speed improvement is enormous. Unfortunately, all the external drives I have plugged into my Mac are now ejecting when the system is in sleep mode and I get the dreaded “Disk improperly ejected…” message. I’m not sure if this is an issue with El Capitan (was running Yosemite formerly – when booting from the mini itself – with no problems), or if it’s because the externals are plugged into the mini instead of the SSD that I’m now booting from. Anyone else with this issue? Thanks.

  • Sean
    Posted October 13, 2015 at 3:59 pm 0Likes

    Great article. I’ve done this with a TB connection to an external SSD on my Mac Mini (mid 2011). Huge speed increase. The only issue is that external drives connected to my mini, seem to eject (improperly) when CPU is in sleep mode. Not sure if this is because I just installed El Capitan or because the drives are not connected to the boot drive (the new external SSD). Has anyone else had this issue?

  • Updesh
    Posted November 14, 2015 at 6:24 am 0Likes

    Excellent article. Do you have any suggestions for what enclosure to use for the Samsung SSD ( SATA III) EVO 850 I just bought. My Mac has thunderbolt, firewire 800 and usb 2 ? ( don’t really want to use USB 2). Thanks!

    • Stella
      Posted September 2, 2017 at 4:00 am 0Likes

      I have EVO850’s and have successfully used both a Mercury Elite Pro enclosure from OWC and an old thunderbolt Lacie Rugged case that I had laying around. In your case an enclosure that runs to thunderbolt will be your best option.

  • Robeiii
    Posted March 11, 2016 at 7:39 pm 0Likes

    my old iMac Died. Found out it was a hard drive issue. Instead of busting open my iMac or paying $400 to have someone else fix it. I tried a modified version of this option. Had to go with a Firewire HHD external drive since my mac doesn’t have Thunderbolt or USB3.
    So i’m not speeding up my mac I was able to bring it back to life and not noticing any significant lag.
    So now my iMac is back just with an extra hard drive sitting under it.

    Thanks so much!

  • rinks
    Posted May 16, 2016 at 7:22 pm 0Likes

    Is there any way to get the SSD drive icon off the desktop? It shows up like it’s removable storage when it’s actually the drive running the OS.

  • Mike Armstrong
    Posted June 1, 2016 at 6:56 am 0Likes

    Hi Robin
    I have just purchased a 21.5 iMac 4k and only later realised it has a 5400rpm Int HDD which slows down an otherwise amazing machine.
    My question is: If I purchase an external Thunderbolt 2 SSD and use this is the main drive/Boot Drive…will it be faster than the current internal HDD?
    And do your instructions above still stand for new iMac using OSX El Capitan?
    Many thanks in advance.

    • Robin Monks
      Posted October 2, 2016 at 8:34 pm 0Likes

      It would be significantly faster, Thunderbolt is the preferred way to do something like this, and it will working with El Capitan and Sierra as described above. Best of luck to you!

  • Dave Epps
    Posted June 22, 2016 at 8:22 am 0Likes

    Hi Robin I have a 2.8ghz 21.5 inch late 2015 iMac I’m looking to speed it up with an external ssd drive as I’m fed up with bouncing apps and the spinning beach ball when doing normal operations like opening photos etc would connecting an ssd drive help speed this up thanks Dave Epps.

    • Robin Monks
      Posted October 2, 2016 at 8:34 pm 0Likes

      The instructions above will work with El Capitan and Sierra as well, just adjust the install phase accordingly for the new version 🙂

  • Bob Lee
    Posted August 25, 2016 at 12:11 am 0Likes

    Your article was very clear…. just need to update with a few questions….. have you ever upgraded to El Capitan with this set up? If so, any issues with using the external as a start up drive?

    • Robin Monks
      Posted October 2, 2016 at 8:35 pm 0Likes

      The instructions above will work with El Capitan and Sierra as well, just adjust the install phase accordingly for the new version 🙂

  • Eduardo
    Posted February 11, 2017 at 8:10 pm 0Likes

    Any thoughts on how to deal with a huge iCloud drive on sierra since it can’t be moved out of the boot hd?

    • Robin Monks
      Posted February 11, 2017 at 9:20 pm 0Likes

      Sadly for now Apple has locked this down a lot. iCloud Drive files do get removed as space is lowered, but, you have to keep it in the boot drive 🙁

      • Guy
        Posted February 24, 2017 at 10:41 pm 0Likes

        Hi Robin

        Thanks for your brilliant article and continued feedback, it has been very helpful in setting up an external SSD [Samsung 850 EVO 250GB] on my late 2012 27″ iMac.

        The computer now takes 30seconds to boot from the external SSD using USB port [I assume this is a USB 3 port on this machine?], rather than 50seconds when booting from the internal HD. I have tried both fresh install and CCC and the cloned boot drive is faster.

        Is this the kind of speed increase you would expect, or do you, like me, think this is a little underwhelming – I was imagining something like 10seconds? Could this be the difference between Thunderbolt and USB 3?

        Thanks again for you help

        • Robin Monks
          Posted May 2, 2017 at 6:09 pm 0Likes

          USB 3 should be fine; however the port, cable and drive must all be USB 3. I’d check to verify that’s the case.

  • George
    Posted March 2, 2017 at 8:37 pm 0Likes

    Hi Robin,

    Great article! I had successfully installed OSX in external SSD (Samsung T3 SSD 500gb) by following your instruction, and the speed improvement was tremendous! But I’ve got one question: how should I reuse my internal HD as files back up drive? I don’t see internal HD icon in Finder so how can I access my old files in internal HD? Thank you in advance.

    • Robin Monks
      Posted May 2, 2017 at 6:07 pm 0Likes

      Opening Disk Utility should let you mount your internal drive. From there you can choose to format it and use it for a backup drive.

  • Hannoodle
    Posted March 14, 2017 at 3:02 pm 0Likes

    Hi Robin,

    Just installed Sierra on mine and it works well (only one day in!!), great instructions seeing especially as I’m not that techie. Got a Rugged with Thunderbolt and USB3 so hopefully now I can use the USB port to speed transfers up as well.

    One immediate question though, my thunderbolt connection doesn’t seem that secure or tight. I’ve already accidentally unplugged the cable while scrabbling about for a USB cable (luckily before I’d installed it as the boot drive). I will endeavour to tidy away the cable but it’s going to get yanked out eventually! The cat once tipped my mac on to the floor! I’m sure he’d love to play with a nice cable…

    Anyhow, do you know of any Thunderbolt clips or fastners that might secure it and stop this happening? My cable is hard wired to the drive so it’d have to be an attachment. I’ve had a google but nothing crops but perhaps my search criteria is wrong (I mostly get links to Kensington Locks). Otherwise I might have to Macgyver it with cable ties and duct tape!


    • Robin Monks
      Posted May 2, 2017 at 6:08 pm 0Likes

      This is, sadly, purely a matter of the cable build quality. You may simply need to get a new cable 🙁

  • briantium
    Posted August 23, 2017 at 9:23 pm 0Likes


    I bought an iMac 2017 27″ with the 2 TB Fusion drive, and I find that it lags with certain programs/files/etc (I suppose whatever is not on the 128 GB SSD portion).

    Its boot up time isn’t bad at about 18 seconds—albeit several seconds slower than my 2014 MacBook Pro that has an SSD drive—so would it make any sense to try to boot it externally from a 500 GB USB-C drive (which I have)?

  • Aditya Chordia
    Posted October 13, 2017 at 5:16 am 0Likes

    I have upgraded iMac (Retina 4K, 21.5-inch, Late 2015) Mac OS High Sierra with Samsung T5 500GB and it is working like a charm. With the stock 5400 RPM HDD the Read write speed was ~ 72MB/s and with SSD it is now 412MB/s and this is reflected in the iMac’s performance.

    I faced an issue during preparation of the SSD for GUID partition. When I plugged in my SSD and used the Disk Utility, the partition tab was not enabled, not allowing me to create GUID partition table. After bit of search I could find the resolution on the apple support (https://discussions.apple.com/thread/7338380?). The issue was resolved by running following command from Terminal

    diskutil erasedisk hfs+ External GPT /dev/disk2

    Very happy, thanks you for this post.

  • Guillaume
    Posted July 30, 2018 at 1:33 am 0Likes

    Great article! I was trying to figure out why my Mac Mini was being so slow while I wasn’t even pushing its capabilities…added an external ssd per your recommendations and it fixed the issue. Night and day! Thanks!

  • Gerald
    Posted September 21, 2018 at 2:50 pm 0Likes

    Wow, what a great read this all is.
    I can’t wait to get an SSD drive and try this with my Late 2012 iMac 2.7 with Sierra.

  • Robert
    Posted January 8, 2019 at 2:10 am 0Likes

    Hi Robin,

    I am about to go with your option of an external drive for 3 ageing Macs (iMac and Mac Minis 2009 to 2012 vintage). One retailer (in Australia) has suggested that the internal replacement option will result in faster processor speeds due to the external connector (e.g. Thunderbolt connector). I presume this is probably correct, but that the loss of speed will be very small given the connector can handle speeds greater than the drive itself. Any thoughts? Thanks Robert
    PS. I prefer the external drive option for the desktops, but might go with an internal replacement for my 2011 MacBook Pro.

    • Robin Monks
      Posted June 14, 2020 at 4:45 am 0Likes

      Your effective speed will be whatever is slowest component is, in your case, the drive. Internal vs External will make almost no effective difference in this situation.

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