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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