Using the Samsung 840 EVO SSD Performance Restoration Software on a Mac

In late 2014 Amazon had a great deal on the Samsung 840 EVO SSD, and I took the opportunity to upgrade my aging MacBook Pro with it. Replacing the original hard drive was quick and easy, and the improvement in performance was obvious and profound. Anything involving disk access now seemed instantaneous.Samsung 840 EVO SSD in MacBook Pro Soon after, I read on Anandtech that Samsung acknowledged a serious performance bug with the 840 EVO SSD that would dramatically slow down read performance for data that had not been rewritten in a while. The bug fix came out in October 2014, first as a Windows application, and with a Mac/Linux version promised by the end of October. As a Mac user I naturally waited until the Mac version came out and fortunately it became available for download a few days before the end of October. Unfortunately, the next challenge was to figure out how to install it.

Update: (April 28, 2015) PC Perspective reports that Samsung has released another firmware update EXT0DB6Q, with a downloadable ISO image for Mac users, to try and finally resolve the 840 EVO performance problem after it turned out that the first update didn’t completely work. This new version EXT0DB6Q is more recent than the version installed by the software in this article. I successfully applied firmware update EXT0DB6Q to my 840 EVO using the same CD technique I describe later in this article (“Creating a bootable optical disc with the fix on it”). Mac users should note that the linked PC Perspective article says the ISO image can be installed on computers without optical drives using “a tool such as Rufus.”

Getting the software

You can download the Samsung software from the Samsung SSD Downloads web page.

Update: As of April 23, 2015, the Samsung SSD 840 EVO Performance Restoration Software section has been removed from the Samsung software page. It has apparently been replaced by the new firmware noted in the other Update above.

Samsung 840 EVO Performance Restoration Software on Samsung SSD downloads page

But the Mac updater came in a form I didn’t expect. While the Windows version is a point-and-click Windows application that lets you use the computer while it works in the background, the “Mac/Linux version” is actually a command line utility and has to be installed on a CD or USB drive that you can boot the Mac from. But the Mac version does not run under OS X, so you can’t use any solution that involves a drive that boots into OS X. That means you have to come up with a bootable non-OS X USB flash drive or CD, something that can be challenging for a computer user who has limited or no experience with a command line.

(Almost) creating a bootable USB flash drive with the fix

I first thought I could just download the “Bootable USB disk” version of the software ( and image it onto a USB flash drive. But the Samsung “Bootable USB disk” version isn’t actually bootable on a Mac from a USB flash drive. It contains only the Samsung utility, no bootable operating system of any kind. After looking up various instructions on the Web I was able to use Terminal to copy the image to a USB flash drive I formatted as MS-DOS FAT, but the drive was not visible in the list of volumes you get when you hold down Option while starting up a Mac, even after I found FreeDOS and added that to the disk image. A little more research revealed that you can’t boot a Mac from a USB flash drive unless it has the right EFI boot loader on it, and that isn’t included with either the Samsung updater or FreeDOS. You have to find the bootable USB flash drive software and figure out how to put it together on your own. Samsung actually warns you about this in the accompanying Installation Guide (PDF):

If you use a USB device 1) Please set your USB drive into a “bootable” state before starting the Performance Restoration software. 2) For assistance on completing this step, please refer to USB boot utilities from a trusted internet site.

Thanks a lot, Samsung. Basically this means if you don’t have the technical expertise to set up your own bootable USB flash drive, which usually requires Terminal commands, you’re out of luck with the USB flash drive option. (A couple months ago I successfully used the Terminal to copy another company’s DOS software onto a USB flash drive that did boot my Mac, but that’s because that company first made sure their disk image had everything necessary to boot a Mac. Samsung didn’t.)

While I’ve been using computers long enough to be the guy that my friends turn to for troubleshooting OS X and Windows and installing hardware upgrades, my Terminal skills are limited. I had already spent some time trying to figure out the bootable flash drive question and I probably could eventually, but after trying a few things that didn’t work I decided my time is better spent on other things. And I was thinking of all those other users who never even go near the Terminal: What should they do?

This is where I’ll ask for your help. If you know how to easily use OS X-based tools to create a bootable USB flash drive that can load a DOS-based (not OS X-based!) updater, or at least how to modify the Samsung or FreeDOS disk images so that the Mac can boot off it and the Samsung software will run, please post your instructions or links in the comments at the end of this article. Bonus points if it can be done with point-and-click (not Terminal) steps!

Update: Here is a possible solution. I haven’t tried it yet. Tutorial USB bootable SSD Firmware SAMSUNG 840 EVO (French, link is Google Translate for English). Also, readers are starting to add ideas to the comments, so check there too.

Creating a bootable optical disc with the fix on it

My MacBook Pro is old enough that it still has an optical drive, so I decided it was time to try the bootable optical disc option instead. I grabbed an old CD-RW (others have successfully used a writable DVD) and used the Quick Erase feature of Apple Disk Utility so that I could reuse it. Then I got ready to burn the Samsung ISO image to the disc. If you haven’t done this before you might find steps on the Web that tell you what Terminal commands to type, but I decided to see if I could simplify those steps far enough to avoid using the Terminal, and I was able to. The only software you need is Disk Utility, which is already on your Mac. These were my steps:

  1. At the Samsung downloads page, download the “Samsung_Performance_Restoration.iso” disk image.
  2. Rename the disk image filename extension so that the filename reads:
    If you don’t rename the disk image, Disk Utility will just burn the single unopened ISO file onto the disk, and that’s not bootable. But when the disk image has a .dmg extension, Disk Utility will make the optical disc identical to the contents of the disk image, which is what you do want.
  3. In Disk Utility, choose Images > Burn, select “Samsung_Performance_Restoration.dmg” and click Burn.
  4. Put the blank optical disc in the optical drive and finish burning the disc. When you’re done it should look like this:
    Samsung Performance Restoration software successfully burned to a CD

You can then continue below.

Running the update

Depending on the size of your SSD the update process may take an hour or two, and once you start it you must not interrupt the process. (Update: Unlike the Samsung Performance Restoration software that is no longer available, the currently available EXT0DB6Q firmware updater only takes a minute or two to run.) It shouldn’t erase data, but with an operation like this you never know. So before you get started:

  • Back up the entire drive. If you are using Time Machine and its last backup was a few minutes ago, you should be set. Also, make sure you understand how to restore the entire drive from the backup.
  • Run the fix only when you won’t need to use the computer for a few hours.
  • If it’s a portable Mac, be sure it’s plugged into AC power since the process could take a long time to complete.
  • If FileVault is turned on, turn it off. The tool won’t work if the drive is password protected. (An OS X user account password is OK, you don’t have to remove that.)
  • Read the section “General Limitations” in the software’s Installation Guide for additional cautions.

To use the bootable media, insert it and then restart the Mac while holding down the Option key. This displays the list of connected bootable volumes. Select the volume with the update on it (in my case the CD) and press Return. (You should also be able to boot directly into a CD or DVD by holding down the C key as the Mac starts up.)

From this point on, the Samsung Performance Restoration utility takes over and works pretty much as it says in the Installation Guide. If you haven’t used DOS-based software, be aware that it’s all keyboard-based so forget about the trackpad or mouse, and pay attention for times when it asks you to do things like press the “y” (for Yes) key or press the Enter key.

[Note for German users: Reader Dirk Lehmann points out that “As a german…while using the DOS-lines one has to use just the same button that is on the english keyboard known as ‘Y’ …On german, Swiss and Austrian keyboards this is NOT the “Y”, but the “Z” button since we use “QUERTZ” instead of “QUERTY” keyboards.]

The tool first installs a firmware update on the drive itself. When the tool says “Downloading Firmware…” I assume it means it’s downloading the firmware from the bootable media into the drive and not actually downloading over an Internet connection, but I’m not sure.Samsung Performance Restoration utility progress after firmware updateWhen the firmware update is done, the software goes through a two-step process which includes recalibrating all the data on the drive. This can take a while and it depends on how big your SSD is. For my 1TB SSD, it took about two hours total. Do not interrupt the process. One odd thing is that the Start Date and Start Time on the screen were three hours ahead of the actual computer clock, I don’t know why.Samsung Performance Restoration utility with all steps fully completedWhen it says “Samsung SSD 840 EVO Performance Restoration completed,” it’s safe to restart the Mac. At this point you can just hold down the Power button on your Mac until it turns off, then press the Power button again to start back up. If you want to eject the optical disc, hold down the mouse or trackpad button during restart and the Mac will pop out the disc before it even gets to the desktop.

If you want to read a more technical yet reasonably simple explanation of the bug, read the AnandTech article Samsung Releases Firmware Update to Fix the SSD 840 EVO Read Performance Bug. For even more detail about the bug, the solution, and the update process, I recommend the article Samsung 840 EVO Performance Restoration Tool preview – Getting EVOs back up to speed at

After the update

I was very relieved to find that the Mac rebooted right back into the regular OS X login screen and everything seemed to work just fine. Running the Samsung utility did not erase data, so I didn’t have to restore from a backup. I still took the precaution of running DiskWarrior on the SSD just to make sure the disk directory was OK (you can also use the Repair Disk feature of the First Aid tab in Disk Utility). Also, if you turned off File Vault as I did, remember to turn it back on.

Once you run the Samsung Performance Restoration software the fix is permanent, and you can’t run the updater a second time on the same drive, so you can go ahead and reformat and reuse the optical disc or USB flash drive you used to apply the Samsung Restoration software.

I know that optical drives are almost nonexistent in the currently available new Macs, so while the CD option worked for me I hope someone can shed light on how to create that bootable USB flash drive so that this article can be useful to more people.


  1. Unfortunately the restoration tool doesn’t work if you use an external cd drive, because the dos doesn’t boot. I have a mac book 11 where the cd drive was replaced by the old hd and the old hd was replaced by the ssd. I think i will put the ssd on a external case to be update from windows

    1. 2012 Mac mini with (cheap) external Samsung burner connected via powered USB hub. Working for me. Update is running Step 2 as I write this.

    2. I got mine to work. First I used the .ISO file (do not change to .dmg). be sure DVD drive is connected directly to mac not through a hub or TBD. Then option boot and look for “Windows” disc and start. All went fine.

  2. If you have access to PC there are lots of tools that will create the USB for you. I use Rufus:

    Just run Rufus, tell it which USB stick to use and point it towards the ISO and it will do the rest. Then just stick the USB stick in your Mac and hold down option at boot in order to use it.

      1. The “Rufus” solution doesn’t work for me; if I select “MBR partition scheme for BIOS or UEFI computers”, the stick doesn’t appear in the Bootable devices; if I select “MBR partition scheme for UEFI computers”, it tells me that “When using UEFI Target Type, only EFI bootable ISO images are supported. Please select an EFI bootable USO or set the Target Type to BIOS”.

        So I’ve followed successfully the solution suggested in the french forum.

  3. Thank you for the input, worked like a chime only one note I had to boot from my external disk, and then restart with pressing the (alt). from there you can choose the windows image to start up…!! In my case it took 20 minutes..:-) for the 250 evo SSD.

  4. Finally something that worked! I burned a few disks en tried the USB card options but I couldn’t get it work.
    Thanks a lot.

  5. Thanks for posting this detailed summary. I was on the verge of buying an 840 EVO for my four year old MacBook Pro, but I think it is ridiculous that Samsung only provides native software for Windows – while at the same time maintaining a webpage declaring that their SSD’s are perfect for your Mac. It’s sickening that they expect the customer to go through all this trouble to fix their flawed drives. I’ll either be waiting for new drives that don’t have this flaw to be manufactured and shipped or just go with another company’s drive.

  6. I’ve been getting the…
    Firmware Update Failed.
    Samsung SSD 840 EVO Performance Restoration Failed.
    After …Downloading Firmware…………and about 15 lines of dots

    I went back to make sure my filevault was turned off, but still get the same message.

  7. Hello, I have succesfully updated, but It looks, that some files are still reading very slow. Do you have any aplication that can prove it? Like HD Tach on windows? I am working on Mac..
    Thank you

    1. I don’t know how to verify on a Mac that the Samsung tool did the right thing. All I know is that the people at tested the difference (see link near end of article).

      Since the Samsung tool has no options and will not let you run it a second time, I’m not sure what you can do if you somehow determine that it didn’t do the job. I assume the Samsung tool has its own verification routine that it must pass before saying it’s complete.

      1. @conrad Hi Conrad, when I first read about thie Samsung 840 EVO SSD thing, I immediately launched System Information via Spotlight, and went to SATA/SATA Express to verify what my Samsung Revision was. Unfortunately, it was, and is, EXT0BB6Q – so I’m one of those who need to go and update my Firmware to EXT0BC6Q.. Wish me luck!

        You should see EXT0BC6Q there if your update has been done properly.

  8. Anyone know if the Samsung Evo has to be the primary boot drive?
    Also, does it have to be connected by SATA? Can I update an external drive via USB?

  9. Use a 2nd machine whether pc or mac with an optical drive for a mac mini using remote disc ( ) or would getting OS X installed onto the SSD and then using boot camp to install Windows. Once windows is installed, boot into windows via bootcamp and then try and update the SSD whilst booted into windows via Boot camp ?

    Just a couple of thoughts, not sure if it would work or not. Probably better off as above using a memory stick or optical disc.

    1. Yes, I expect that having a second computer would make it possible, especially if the second computer is running Windows. I think I’ve also seen reports from users who fixed their Mac drive before the Mac version was available, by running the Windows version of the software from a PC or Boot Camp. But I wanted to focus on solutions that work if the only computer you own is one Mac, because I know so many people where that is the case.

      The real problem here is that Samsung puts out a version that they say is for Macs, but if it won’t work for some users unless there is a PC in the chain somewhere, how much value does it have as a Mac version? They might just as well say, if you want to fix your Mac drive, download the PC version and go find a friend with Windows.

    1. Hi Emanuele, as noted in the article and in the Samsung documentation, the Samsung Performance Restoration software allows you to run it only once. Running it also updates the firmware so that the problem doesn’t happen again. You cannot run it a second time.

    1. Not through Parallels. No reason to try that anyway. I got mine to work. First I used the .ISO file (do not change to .dmg). be sure DVD drive is connected directly to mac not through a hub or TBD. Then option boot and look for “Windows” disc and start. All went fine.

  10. Can anyone with the Samsung 840 evo running inside a mac run the BlackMagic Disk speed test to see if after the firmware and and restoration process you get read/write speeds faster than 255/250 cause thats the neighborhood im getting. And I’m not sure if I did it right

  11. Someone on a another site said because my imac was 2010 (I believe or it might have been early 2011) im probably on sata 2 which is why im getting 255. If that’s all I can get that would really suck.

  12. 2012 Mac Mini, 1TB 840 EVO as boot and only drive. Burned the ISO (didn’t rename) to CD using Disk Utility and an external DVD drive connected to Mini through a powered USB 3.0 hub. Did the Option boot with the drive connected to the hub…booted to the “Windows” CD presented on screen and is now at “Step 2 in progress…..” that’s 5 dots after 10 minutes from starting the DOS utility. Hopefully it all finishes up with no issues….but I did make a clone of the SSD using CCC before I started all this.

  13. Thank you for the article!
    I have a few questions. I have the 840 EVO 500GB on my 2008 MacBook pro (10.9.5 + Bootcamp W7). I just want to confirm that I only run the tool on Mac or Bootcamp. I don’t have to run it both partitions, correct?

    Also if I run it and update it to 10.10 Yosemite, do I still need to run Trim-enabler?

    1. The Samsung software fixes the entire drive, so it doesn’t matter which partition you fix it from. Once finished, it apparently won’t run a second time on the same drive anyway.

      The Samsung software doesn’t affect the TRIM issues with Yosemite. If you want to use Trim Enabler in Yosemite you still have to disable the security setting that prevents Trim Enabler from running (

  14. Thank you so much for this guide. It was clear and easy to follow. The update took about an hour for me with a 249 GB disk with 129 GB of free space (just in case this is useful to others)

  15. Thank you so much. Excellent article. Found this while I was trying to do it by making a bootable USB drive with the stuff from the Samsung Website (which appeared to be futile). All worked for me once I found a very old CD-RW. haven’t used the built-in CD ever. MBPro 2010. 🙂

  16. About a month after using the Performance Restoration Software the performance problem seems to occur again!? Could this be because the EVO is a third party drive and therefore OS X doesn’t support it with the TRIM command?

    1. If using any OS prior to Yosemite then install trim enabler. However even without Trim let garbage collection work a long time by option booting and let it stay in this mode overnight. Then the system will clean up the files. My Mac Mini with the EVO works great.

    2. Be sure you keep the issues straight, it sounds like you have associated multiple issues that are actually unrelated:
      1) Lack of TRIM support in OS X would not cause a slowdown this quickly.
      2) The fact that it is third party is not automatically a problem, because some third party SSDs do not need TRIM under OS X.
      3) The performance problem discussed here is specific to the Samsung EVO 840 only. It isn’t related to issues regarding OS X or TRIM or other third parties. It was about how the 840 EVO controller was managing the data on the drive.

      I haven’t heard of the performance problem recurring. Are you sure it’s the same problem, as described in the PCPer and Anandtech links in the article, where only old data slows down but new data is still fast? If you are seeing that all types of data now have slow throughput, that’s a different problem than this one.

    3. Update: There have been a number of reports that the Samsung Performance Restoration Software may not have completely fixed the problem it’s supposed to fix. Samsung has issued a statement saying they will be coming out with another software update. For more information, read these articles:
      Samsung Promises Another Fix for 840 EVO Slow Down Issue
      Samsung Releases Statement on 840 EVO Performance – Another Fix Is In the Works

      Again, the problem addressed by this software is completely unconnected to issues related to OS X support for TRIM.

  17. Very informative article – thanks. I do have a question:

    The updated firmware is listed as EXT0BB6Q. System Information on my MacBook Pro shows that current firmware version on my 500Gb 840 Evo is EXT0CB6Q.

    Do I have a newer version of the firmware? It seems to me that CB should be newer than BB, but what do I know?


    1. To clarify, in the first MacBook Pro screen shot you see in the article, it shows EXT0BB6Q as the version before I ran the Samsung restoration software.

      After running the restoration software I now have EXT0CB6Q, according to System Information.

      I wrote the article back when everybody had the old firmware. Now that a few months have gone by, there’s definitely confusion if you just bought an EVO 840 because now they’re probably all coming off the assembly line with the new firmware and the bug already corrected. I hope.

  18. Thanks for the post, I’ve spend three hours in making a USB key bootable from “”.

    I can confirm that the way suggested by the french forum ( runs very well!

    The “Rufus” solution doesn’t work for me; after I had selected “MBR partition scheme for UEFI computers”, it told me that “When using UEFI Target Type, only EFI bootable ISO images are supported. Please select an EFI bootable USO or set the Target Type to BIOS”.

  19. Thanks for you blogpost. Very very helpful… I am experiencing too lots of troubles with bootable USB… My current task, find a DVD-RW somewhere

  20. Thank you for your info. I am a noob and just strictly followed your instructions on my macpro 2011 and evo 840 . It is now updated and run at 500 . Thank you soo much

  21. Hi,

    I just updated the firmware as shown in the article. BUT no Performance Restoration took place after upgrading the firmware.

    It just said: Firmware upgraded, than rebooted and went into the login screen of the mac.

    I have an external CD to USB because the internal is SSD primary and HDD secondary into the mac.
    I tried to reload the Boot cd but it says “firmware already upgraded” and don’t let me do anything. So NOW how should I do to run the performance restoration tool? is that any way to do that?

    Thank you

    1. The latest firmware actually does the restoration proces over time itself, thus no need for a separate restoration tool. The original idea of Samsung’s engineers didn’t work out, the reconditioned drives started to slow down again. So this is kind of a brute force solution. Time will tell if it works in the long run…

  22. I have a late 2013 MacBook Pro ( OS X 10.9.5) Mavericks with an internal Superdisk drive so I am rather new to Mac. I installed the Samsung EVO 840 some time and use the original Apple hard disk as a back-up using Time Machine. Three days ago, I downloaded the firmware pertaining to EVO 840 from the Samsung website. There are no instructions on said site pertaining to this download anymore. I followed your instructions and changed the iso extension and then burnt it to CD. The burnt CD shows the same files as outlined in your article. However, I have been unable to restart using the CD as the boot disk. I have tried pressing the Option key on restart, but it does not show the CD disk at all. I tried also pressing the C key on restart, and the Command (.) keys. None worked. I repeated this several times but the same result occurred each time. Any suggestions would be appreciated.

  23. Problem solved. I used a CDR instead of a CD R&W. When I used the latter, everything worked – did not even have to change the download extension from iso to dmg

  24. Hi Conrad, just a bit confused:
    You say
    You can download the Samsung Performance Restoration software from the Samsung SSD US Solid State Drive Downloads web page.

    And the screenshot image you have posted is not what I am seeing.

    Note that to fix the performance bug, you must download the updater from the “Samsung SSD 840 EVO Performance Restoration Software” section, not the “Samsung SSD Firmware Updates for Mac Users” section.

    I can only see Samsung SSD “FIRMWARE” Updates for Mac Users which you say NOT to use.
    Could you point me to the latest correct link?

    1. Sorry about the confusion. That was because Samsung originally provided a utility that was not in the firmware section and that’s how I wrote the original post, then more recently they removed the utility and provided a new firmware update. I’ve updated that part of the post so that it’s more current since it looks like the old Performance Restoration utility is not coming back. Thanks for pointing it out!

  25. Hey Guys,
    maybe anyone of you know a resolution for my problem.
    My 2011 Mac Mini without internal CD/DVD-Drive, boot the CD from an external LG Drive.
    But they don’t recognize my USB-Keyboard. I can’t “press any key to continue…”
    Anyone an idea?

    Thank you an BR

  26. THANK YOU very much for this perfect description how to do the Firmware update by internal optical dríve!!! :-)))

    Worked perfectly like a breeze (did it by DVD-RW).

  27. I have run their restoration tool on Mac but it didn’t help. Neither formatting this SSD with zeros and cloning system back from regular hard drive like twice. Even running their Magician’s optimisation tool on PC… Nothing helped, it’s still slow. I basically wasted a week of my life trying to recover and now giving up. I want Samsung to replace my 840 with brand new 500GB 850 model, this is the only way they can help me.

Leave a Reply to Craig Lang Cancel reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.