Enabling Trim on OS X Yosemite

Enabling Trim on OS X Yosemite
June 3, 2014 Oskar

This is an old post. Please see the latest post on Trim in Yosemite:




I made a post earlier today highlighting some issues with using Trim Enabler on OS X Yosemite Developer Preview. Good news: Trim Enabler works to enable Trim in Yosemite, no update required! Background story: In the Developer Preview 1, modified kernel extensions are blocked from loading during boot. However, Apple also provided a way to disable this block, by simply adding a boot argument. According to Apple, this block was added for “Developer Preview 1”. which leads me to believe that this block may be removed in the final release of Yosemite. So at this point it seems likely that Trim Enabler will work “out of the box” without this boot argument for the final Yosemite release. But since some users are already using DP1 in their systems, here is a guide to enabling Trim in OS X Yosemite Developer Preview 1 using Trim Enabler:

  1. Remove your current Trim Enabler and “org.Cindori.AuthHelper” in /Library/PrivilegedHelperTools, and redownload the app
  2. Add this boot argument to remove the kext block (run in Terminal):
    sudo nvram boot-args="kext-dev-mode=1"
  3. Reboot

  4. Enable trim using Trim Enabler
  5. Wait ~1 min
  6. Rebuild kext cache manually using this command in terminal (wait for it to finish):
    sudo kextcache -m /System/Library/Caches/com.apple.kext.caches/Startup/Extensions.mkext /System/Library/Extensions
  7. Reboot again



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  1. Z 5 years ago

    Thank you for the quick solution.
    I have a question.
    What will happen when I update to DP2. Shall I have to run this nvrm command again? Will the system halt during the booting?



    • Oskar Groth 5 years ago

      I don’t think the nvram command will not need to be redone, and it will most likely not cause any issues either. It is Apple themselves that recommend the use of this command for DP1 for running unsigned kexts. It’s not clear if it will even be needed after DP1.

      • Hugo 5 years ago

        Hi…I’m using a Yosemite beta, I downloaded Trim Enabler, but when I opened a trim apps, the system show “This version of Trim Enabler could not using with this version of OS X”
        What can I do to run Trim Enabler?

  2. Kissmo 5 years ago

    Hard to say in my opinion.
    I believe to be safe then – you should then disable trim enabler.

    Remove your current Trim Enabler and “org.Cindori.AuthHelper” in /Library/PrivilegedHelperTools

    Then install the DP2.

    Then wait for feedback 🙂

  3. santi 5 years ago

    even if I follow the steps one by one I still end up with a non booting system if I enable Trim in Yosemite, and not only that but after that happens the terminal commands suggested in previous post to make it boot dont work and I have to reinstall.

    what am I missing

    • Si Brindley 5 years ago

      @santi I spent a couple of hours noodling around with this getting my system booting again after hitting the non-booting issue (before this workaround was found). The first time I copied my kext from my Mavericks Time Machine Restore partition… and it worked. Being an idiot, I thought I’d “fix it” some more because I didn’t like that it wasn’t the Yosemite-supplied version of the original files, so I booted the Yosemite Restore partition and applied the fix again. This returned me to non-booting. It took about seven more attempts after that before I booted again, trying from various backups etc. In the end, I suspect the thing I was getting wrong was not waiting long enough for the kext kernel cache to rebuild. So, my advice to you is to wait a good few minutes before you reboot. (Or actually check the rebuild process has finished.)

      • Oskar Groth 5 years ago

        I added an extra step to rebuild the kext cache manually, to make sure you let it finish.

        • Si Brindley 5 years ago

          Oskar – thanks for all your work on this and for quickly finding a workaround yesterday and a better fix today. Much appreciated.

  4. Sebastian 5 years ago

    I recibe the following text

    kext com.jmicron.JMicronATA 101069000 is in exception list, allowing to load
    kext-dev-mode allowing invalid signature -67061 0xFFFFFFFFFFFEFA0B for kext IOAHCIBlockStorage.kext
    kext com.hp.hpio.hp-io-printerclassdriver-enabler 1909009000 is in exception list, allowing to load
    kext file:///System/Library/Extensions/hp_Inkjet8_io_enabler.kext/ is in hash exception list, allowing to load
    kext com.hp.kext.hp-fax-io 511009000 is in exception list, allowing to load

    This is OK?

    • Oskar Groth 5 years ago


      “kext-dev-mode allowing invalid signature” this means that the boot command was applied correctly.

  5. Sebastian 5 years ago

    It’s work fine.

  6. Stephan 5 years ago

    Thank you, you made my day =)

    Greetings from Germany

  7. Dave 5 years ago

    If you don’t want resetting the NVRAM to render the system unbeatable, I recommend adding kext-dev-mode=1 to the Kernel Flags section of /Library/Preferences/SystemConfiguration/com.apple.Boot.plist.

  8. Dave 5 years ago

    If you don’t want resetting the NVRAM to render the system unbootable, I recommend adding kext-dev-mode=1 to the Kernel Flags section of /Library/Preferences/SystemConfiguration/com.apple.Boot.plist.

  9. Sebastian 5 years ago

    Yosemite 10.10 PREV 1 Disable TRIM again. 🙁

    • Oskar Groth 5 years ago

      Just use Trim Enabler again to re-enable (make sure you still have the boot argument).
      And I think you mean Developer Preview 2.

  10. Sebastian 5 years ago

    Yosemite 10.10 PREV 1 – Disable TRIM ENABLE, doing the Procedure work fine for me.

    Add this boot argument to remove the kext block (run in Terminal):
    sudo nvram boot-args=”kext-dev-mode=1″
    Enable trim using Trim Enabler
    Wait ~1 min
    Rebuild kext cache manually using this command in terminal (wait for it to finish):
    sudo kextcache -m /System/Library/Caches/com.apple.kext.caches/Startup/Extensions.mkext /System/Library/Extensions
    Reboot again

  11. Rino Dattilo 5 years ago

    So, please just a question for non super duper programers in “hack” language 🙂

    to add the first sudo just you just copy that in the terminal command and hit enter?

    • Oskar Groth 5 years ago

      Yes, the text in the boxes are meant for copying to terminal.
      But, if you don’t feel comfortable with terminal commands, I suggest you wait out the final Yosemite release where this probably won’t be needed.

      • Rino Dattilo 5 years ago

        Worked great and thank you for the simple directions. I had already messed up the computer so I thought why not work from the terminal.

        A question though – if your mac is not booting these directions don’t work from recovery mode do they? I could not get them to work.

        Thanks again! And before we go to DP3 I will check here 🙂

  12. Chris Hallam 5 years ago

    what about the now current DP 2, will it just work, or are the terminal commands needed?

    • Oskar Groth 5 years ago

      Same as DP1. It’s probably to help debugging for Apple during DP/Beta phases.

      • Chris Hallam 5 years ago

        now by doing the terminal command ,

        1- do we do it before or after clicking enable TRIM?

        2-also will it stay enabled thru upgraded betas or will we have to re do the code on each release?

        3- will there be any harm done if we skip doing so until the Fall, or performance degradation of 3rd party ssd, I have a samsung evo

        • Oskar Groth 5 years ago

          You can check whether the argument is still there by just running “sudo nvram boot-args”. If it is, there is no need to redo it. Just install DP2 and enable Trim after.

  13. JD 5 years ago

    SUCCESS… The 4 line code to fix the boot issue worked too.

  14. Per Larsen 5 years ago

    Any update on compatibility now DP3 is out?


  15. Ryley O. 5 years ago

    I can confirm that these steps do not need to be repeated upon updating to dp2 or dp3

    • Gerhard Rössel 5 years ago

      Do you mean when I update from DP2 to DP3 and did the workaround for DP2, I must not repeat it when upgrading to DP3 ?


  16. tobi 5 years ago

    If you are stuck with a boot logo you can try to disable trim via Recovery Partition and open Terminal.

    rm -rf /Volumes//System/Library/Extensions/IOAHCIFamily.kext
    cp /System/Library/Extensions/IOAHCIFamily.kext /Volumes//System/Library/Extensions/IOAHCIFamily.kext
    touch /Volumes//System/Library/Extensions
    kextcache -u /Volumes/

    Note: if your 10.10 Partition has a name like “Macintosh SSD” you must enter /Macintosh SSD/

    • Oskar Groth 5 years ago

      This is already covered in the previous post:

      • leon 5 years ago

        This doesn’t work for beta 2. I ran the 4 line command in your previous post and waited till it finished. after reboot still ran into prohibition. I installed beta 2 in late August so the latest software should not cause the problem. However, I forgot to run these commands in this post. Is there a way to fix this without reinstalling yosemite since don’t have a backup.

  17. Gerhard 5 years ago

    Is there anybody knowing whether I can activate trim enabler using yosemite dp3 without any problems. Or must I do the same workaround described for dp1?

  18. John 5 years ago

    Working perfectly in DP3 for me!

  19. Drgonzo 5 years ago

    Weird issue for me since DP3, and only when I activate Trimenabler. iTunes home sharing stops working. I’ve tried a bunch of things over the past week, and the final steps seem to indicate that something happening when activating trim enabler is breaking iTunes sharing. Sometimes it lasts for a bit and dies and sometimes it doesn’t work at all. I’ve run without trim enabler for the last 3 days and it’s working fine. Today I enabled it, and instantly I’m having trouble. Anyone else experiencing this? I’m going to go back to DP 2 and see if it’s still healthy there. It seems that they may have changed something with DP3. In my experience it’s also broken in the previous as well s current release of trim enabler. I didn’t experience any trouble prior to DP3.

  20. Fabricio 5 years ago

    Just updated to Yosemite Beta 4 and Trim Enabler won’t run anymore. It is reporting as ‘wrong version’.

  21. Drgonzo 5 years ago

    It seems in the latest Trim Enabler update they enabled version checking. I had a copy of the previous version and this works fine.

    Apple also seems to have fixed (at least so far) whatever was breaking my iTunes home sharing.

  22. Hanz 5 years ago

    Yep – Trim Enabler is disabled on DP4. The developer will need to release a new version for us.

  23. Damian 5 years ago

    If you use version 3.2.2 you can follow the steps described above. Trim Enabler works perfect for me on MBP late 2011. But do not update to 3.2.4. We have to wait for a new version.

    • Matt3o12 5 years ago

      Could you upload version 3.2.2. Can’t get it and I don’t want to my SSD without Trim

    • Fabricio 5 years ago

      Please, do you know how to get that version?

  24. intagli 5 years ago

    You can right click on the executable, show package contents, contents–>macOS and run the executable there, enable trim and restart. It’s now showing TRIM Support: Yes for me on my macbook on yosemite dp4

  25. Hugo 5 years ago

    I’ve just excecuted Trim Enabler from within the package, just do right click on the app (That should have a forbidden sign), then enter the next route: Trim Enabler.app/Contents/Mac OS/Trim Enabler
    This opens a new terminal window and then Trim Enabler, when you do this, you can do the steps from this tutorial.

    I hope this helps.

    • Lennart 5 years ago

      Thanks Hugo! I did as you wrote, and it works fine. Excellent and easy.

  26. mkomman 5 years ago

    Dev 4 it places my trim in incompatible software… i tried the word around but nothings works… when I install Trim enabler there is a sign in it so I can’t use it…. also the word around does not word.


  27. TomCRUISE 5 years ago

    I delete Trim Enabler 3.2.4 before installing DP4, then installed 3.2.2 and it worked fine. I went from DP4 to the beta (kind of pointless) and 3.2.2 gave me an error message. I tried 2.2 and followed the instructions at the top and it seems to be working

  28. SamS 5 years ago

    Anyone tried to enable trim using Trim Enabler version 3.2.4 on the public beta 10.10 (14A299l) that was released today?

    • rep 5 years ago

      yes I have the same problem…I cant open Trim Enabler because of public beta preview made 24 july 2014 (yesterday) I try to follow the below way but can’t open trim enabled :S

  29. Milan 5 years ago

    So I just installed Yosemite public beta and Trim Enabler was removed from Applications. When I follow your instructions it doesn’t work. I re-installed it and it appeared in Applications finally, but I can’t still launch it. When I try it keeps saying “You can’t use this version of the application “Trim Enabler” with this version of OS X.” 🙁

  30. Tim 5 years ago

    This workaround fails on MacBookPro9,2 16 GB RAM. After following all steps, still get message that Trim Enabler cannot run on Yosemite.

  31. Chris 5 years ago

    I’m running the Yosemite Beta (10.10) and I too was unable to get Trim Enable 3.2.4 to run. However, I was able to get 3.1.2 (which I found searching Google for an older version of Trim Enabler) to run using the workaround described in this article. So it seems like this older version has enabled trim on my Macbook. I don’t know if it’s the best solution, but it’s something.

  32. Hakan 5 years ago

    I installed Yosemite beta today, and upgraded Trim Enabler 3.2.4 but it didn’t work.

    Any fixed version will going to be released soon?

  33. wrwolf2 5 years ago

    a) Add this boot argument to remove the kext block (run in Terminal):
    sudo nvram boot-args=”kext-dev-mode=1″
    b) Reboot
    c) Enable trim using Trim Enabler
    Wait ~1 min
    d) Rebuild kext cache manually using this command in terminal (wait for it to finish):
    sudo kextcache -m /System/Library/Caches/com.apple.kext.caches/Startup/Extensions.mkext /System/Library/Extensions
    e) Reboot again

    i now have TRIM Support = YES when running SYSTEM INFORMATION

    bear in mind for step C i had to “SHOW PACKAGE CONTENTS” and drag and drop the TRIM ENABLER from MacOS folder into a terminal session then hit return to run the command. (kept getting error messages otherwise)

    • wrwolf2 5 years ago

      TRIM ENABLER ver. 3.2.2 , Yosemite DP4 and McBook 7,1

      • wrwolf2 5 years ago

        with TRIM ENABLER ver. 3.2.4 -> do SHOW PACKAGE CONTENTS and DRAG & DROP “TRIM ENABLER” from within MacOS folder into a terminal session.

  34. Subeg 5 years ago

    i can confirm that the above works with Yosemite public beta 1 as long as you use 3.2.2, which is available to download on the Cindori website. I have TRIM enabled now and haven’t had any issues yet (fingers crossed)

  35. Hakan 5 years ago

    The method above worked! Thank you. I used 3.2.4, the updated version.

    First i deleted the Trim Enabler program and removed “org.Cindori.AuthHelper” file.

    Later applied the instructions. Now it is working with Trim! In system report, SSD Trim shows enabled.

  36. Ian Sliwinski 5 years ago

    Just started using the OS X Yosemite Beta 1 (14A299i) and post installation the OS reported that Trim Enabler was [Incompatible Software].

    Do I need to re-run the steps you outline above for OS X Yosemite Developer Preview 1?

    Prior to OS X Yosemite Beta 1 Trim Enabler was functioning.

  37. Milan 5 years ago

    Trim Enabler 3.2.4 disabled in Yosemite Public Beta (14A299l). Following your instructions didn’t work. 🙁

    • Hakan 5 years ago

      It should work if done correctly.

      I am also using Yosemite beta and i managed to make it work.

  38. Brink 5 years ago

    14A298i works.
    14A299l does not work. This newest beta build won’t even let you execute Trim Enabler.

  39. Ian Sliwinski 5 years ago

    For clarity:

    Trim Enabler works (after following instructions for OS X 10.10 DP1 in this article) in Build 14A298i.

    Trim Enabler DOES NOT work (even after following instructions for OS X 10.10 DP1 in this article) in Build 14A299i.

    Is there a new build of Trim Enabler I can try?

  40. Dude 5 years ago

    Thank you!

  41. Ben 5 years ago

    Thanks to MatthieuTnsc for posting this fix:

    As some know, “Yosemite” does not work with many app’s.
    Here’s a simple fix that got Trim Enabler running:

    – Open Applications folder
    – Right click on “Show Package Contents” on Trim Enabler Application
    – Open “Contents” then the “MacOS” folder
    – Double click on “Trim Enabler”

  42. Wayne 5 years ago

    Hi All,

    Until Oskar can get his very cool program updated to Yosemite use the following to get Trim on Non-Apple SSDs.

    1. Turn off Trim Enabler
    2. Open Terminal
    3. Paste the following into Terminal.

    sudo touch /System/Library/Extensions && sudo kextcache -prelinked-kernel /System/Library/Caches/com.apple.kext.cache/Startup/kernelcache -K /System/Library/Kernels/kernel /System/Library/Extensions

    4. You will probably have to enter your password.

    Thats it.

  43. Rahm 5 years ago

    Sorry Wayne and the others! The methods you mentioned don’t wirk on the public release! If someone knows thr right answer, please let us know a step-by-step solution to test it. Thank you very much by commenting your resultd under this page :)!

    • Wayne 5 years ago

      Hi Rahm,

      It may not work on the Public Beta but, it is working like a delight on DP4. I have waited 4 days to make sure and it is running like jewel on all 4 ext SSDs I work with.

      Take Care

  44. Rahm 5 years ago

    UPDATE: It works flawless! Just follow the Steps Cidori mentions above but make sure to DON’T restart the computer when you are enabling the trim with Trim Enabler (Step 4). Wait a minute like Cidori has wirtten. Then open a new window in terminal and copy/paste Part 5. Wait until the usual command line will appear (hard drive name, etc.). Then restart!

    So happy now 🙂 – just did the mistake with the reboot before using step 5.

  45. Thimmy 5 years ago

    Hi every one. After changed the kext mode like explained by the Cindori Software support, you have to install TRIM Enabler version 3.2.4, and go to the Applications folder. Right click on TRIM Enabler icon and select “Show packet content”. A folder will open. Click on “Contents” folder. Open the folder called “MacOS” and you will see a file called “Trim Enabler”. Open Terminal and drag and drop “Trim Enabler” into.
    Now you can enable TRIM for your SSD on your MacBook.
    I did it with the steps I gave you and it work fine for me.

    Have a nice day and Aid Mubarak for muslim people.

    • MacManux 5 years ago

      Yeah, great, Thimmy, that did the trick! Works fine again under the public beta of Yosemite! Many many thanks!

  46. Andrei 5 years ago

    The old enabler seems to have worked…

  47. Alex 5 years ago

    I installed the public beta of Yosemite and like the others told before I have the same problem with starting the Trim Enabler. Is there no chance to make it work on 14A299l ? Whenever I click on Trim Enabler it says that the program ist damaged and should be put into the trash can.

    Will the SSD take damage without an enabled trim function?

  48. Vincent 5 years ago

    First: THANKS!!! I have my Mac back! I had the problem with the stop sign.

    But I have an other Problem now: I can download “Trim Enabler” the normal way, but when i want to open it. OS X say that it is damaged. What can I do?


  49. Robert 5 years ago

    Just tried this fix in OS X Yosemite DP5 a couple seconds ago and after deleting and reinstalling Trim Enabler and putting in the first terminal command and then rebooting, I tried running TRIM Enabler and the computer said TRIM enabler is a broken App and should be moved to the trash. Cindori do you know why this is happening and is there a fix?

  50. CooSee 5 years ago

    thx, but doesn’t work for me 🙁

    how to switch back ?

    good to have working mavericks.


  51. ethan 5 years ago

    Just today I launched the Trim Enabler of a old version and it pop up a window telling me that there is a update.
    After the update, the application automatically enable the trim feature without manual type of command in Terminal and after rebooting, I got Yes in the system report for the trim support.
    Under the old version of Trim Enabler, I cannot enable it even trying several time by typing the commands in terminal.
    Worth to try the version 3.2.6 of Trim Enabler.
    Good luck, guys!

  52. Simon 5 years ago

    Anyone have luck upgrading to beta 2? I attempted today and am.sitting at a screen with a circle and line going through it. I attempted restoring the unmodified IOAHCIFamily.next file as outlined on another page here without success. Hoping I don’t need to reinstal. :p

  53. Anonymous 5 years ago

    This is a bad tutorial.
    There isn’t even sudo in BaseSystem.dmg

    Causing confusion for non coders.

    • Oskar Groth 5 years ago

      This is not intended to be run in the Recovery Mode, and there is a large title directing you to a new and more relevant post.


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