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




  1. ethan 2 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!

  2. Simon 2 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

  3. Anonymous 2 years ago

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

    Causing confusion for non coders.

    • Author
      Oskar Groth 2 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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