Trim in OS X Yosemite

Trim in OS X Yosemite
June 3, 2014 Oskar

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


Just a quick update about the status of Trim in Yosemite.


Yosemite still limits Trim to Apple only SSD, like other OSX

Trim Enabler runs fine and seems to add Trim support just like before

However, kernel extensions that have been modified are no longer loaded by OSX, so you will get a boot failure after enabling Trim


For now I recommend to not enable Trim in OS X 10.10 Developer Preview.

I have every intention of adding 10.10 support for Trim Enabler, and I’m working to fix this.

If you went ahead and enabled Trim and find yourself unable to boot, you can reset the Trim driver by following these steps:


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



If you want to discuss or get help with Yosemite, use this topic:


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  1. nos1609 5 years ago

    Maybe it might help in further developement.

    “In Developer Preview 1 unsigned or improperly signed kexts will not be loaded. To use unsigned kexts during development, this strict check can be disabled by adding a “kext-dev-mode=1” boot arg
    by Netkas ©”

  2. William 5 years ago

    This fix did not work for me. Is there another way to get my Mac up and running? I still can’t boot after removing/copying that kext across successfully

  3. Matt 5 years ago

    Didn’t work for me either. In verbose mode I get “Still waiting for root device

  4. stevenB 5 years ago

    Thanks, this actually fixed my mac after using trim enabler

  5. John 5 years ago

    I just had this same problem. I still had my old hd with me had to erase the new SSD and then reinstall it. long story short, Good thing I had my old hard drive with me. cmd-r did not work for me.

  6. tomM 5 years ago

    With the today announced public Beta of Yosemite you can’t install the actual release of Trim Enabler

  7. LiudasBar 5 years ago


  8. ranio 5 years ago

    Can not work on my Fusion Drive, even after I set the permission of the extension like following,
    chmod -R 755 /Volumes//System/Library/Extensions/IOAHCIFamily.kext
    and then:

    chown -R root:wheel /Volumes//System/Library/Extensions/IOAHCIFamily.kext

  9. Tim Standing 5 years ago

    Just a quick correction on the above commands. If you have a space in your volume name, the script won’t work. A couple of well placed quotation marks fixes the problem.

    Here’s the corrected commands:

    rm -rf “/Volumes/YourDisk/System/Library/Extensions/IOAHCIFamily.kext”
    cp -r /System/Library/Extensions/IOAHCIFamily.kext
    touch “/Volumes/YourDisk/System/Library/Extensions”
    kextcache -u “/Volumes/YourDisk”

    Thanks for putting this set of commands up.


    • jloe 5 years ago

      Excellent, this modification has saved my life. Thanks for sharing.

  10. Joppe 5 years ago

    So, my Windows partition is also on the SSD and I’ve made a fusion drive setup with my SSD and HDD. I do not have any OS on another HDD in my Mac. Recovery utility isn’t there since setting up the fusion drive (my bad). Leaves me with no option to get into any kind of terminal.

    Bootable USB does not work either. What to do?! I’m getting desperate.

  11. Robert Williams 5 years ago

    I know apple is become controle freaks but in the mean time how about taking this crap of the web or post a big message DO NOT INSTALL ON YOSEMITE UNLESS YOU WANT TO BE SITTING IN FRONT OF YOUR COMPUTER LIKE ITS A FUCKING WINDOWS MACHINE. to many times I forgot to disable this crap and have to reinstall.

  12. Glenn 5 years ago

    You sir, are my hero!!!

  13. David 5 years ago

    Typing this on my iPad since my Macbook Pro is now bricked after enabling trim and installing the gold master download of Yosemite today. So annoying. I am getting the broken circle icon. I’ve tried to reboot with cmd R, doesn’t work. What can I do?

  14. Ricardo 5 years ago

    just made the update to Yosemite today,

    What is the current status for Trim Enabler? Should I enable it or not? When will it be safe to do it?


    • Oskar Groth 5 years ago

      Please wait until later today and I will make a post regarding compatibility and an update if needed.

  15. Metty 5 years ago

    Thx for that workaround. Helped me fine

  16. Eric 5 years ago

    This did not work for me i have tried it a few times how can i just delete trim. i need to get my computer back online.

  17. Nicolai 5 years ago

    Dosnt work for me. After second line, it says strange things

  18. Nicolai 5 years ago

    Ive tried it like five times now. Everything looks like the youtube video, but when i close terminal and reboot, same thing happens. Im very angry right now! F… This yosemite…. How the F… To remove that trim from terminal? Pls help.

  19. Nicolai 5 years ago

    But its the same. Ive tried all commands, from video and from in here. Still no luck

  20. Johnette 5 years ago

    What a pleasure to find someone who idefiintes the issues so clearly