As of Yosemite, DIY, or non-Apple installed SSDs have Trim support challenges using applications such as Trim Enabler. Assuming one keeps their TRIM supported SSD in Yosemite,

  1. what is a good strategy for using Trim Enabler periodically so there are no issues with kext-signing and potential OS update conflicts while Trim Enabler is disabled?
  2. Can this be worked around by periodically using Trim Enabler?
  3. How long should Trim Enabler be run?
  4. How often?
  5. If SSD usage, e.g. amount of read/written data is relevant to how long/often Trim Enabler should be run, is there a way to evaluate guidelines on light, moderate, heavy use.

An excellent feature for TE would be a scheduler to run based on need, then toggle TE off and turn kext-signing back on after a scheduled maintenance run. At least until/if Apple ever reopens kext-signing to software and hardware devs. Cheers -

1 Answer 1


What I used to do was enable TRIM, reboot, create and delete an encrypted disk image that almost filled the free space, leave my MBP idling overnight, disable TRIM, and reboot. That restored performance.

I'm not sure r/w volumes will tell you anything useful. The OS reuses erased blocks and the current controllers garbage collection is supposed to make TRIM largely irrelevant (or at least that's what I read).

I don't have that machine anymore and it seems like a lot riskier process under 10.10 so I'm not doing anything with TRIM on my Mac Mini w/ a Samsung 840 EVO.

  • Interesting strategy. Sorry, to clarify, what is "APand reboot"? I was reading up on TRIM and garbage collection earlier, here's what I learned so far: Trim may be an aid to garbage collection to reduce writes, improving longevity. Sorry to hear you're not using your comp because of this. I'm in limbo on putting a Samsung SSD into my Mac Mini until this gets sorted.
    – thepen
    Dec 22, 2014 at 3:29
  • That was just a typo (fixed). TRIM/SSD had nothing to do with why I got rid of my MBP. Don't let worrying about this issue keep you from upgrading. The safest option is to get a drive from OWC because they are intended for use under OSX. I put an OWC SSD in my wife's mid-2009 MBP and never saw a performance drop even though she ran it 95% full. Only you can say if it's worth the premium. Dec 23, 2014 at 5:17
  • When you said "I'm not doing anything with my Mac Mini w/ a Samsung 840 EVO," does that mean you're not using it because of the TRIM issue or something else?
    – thepen
    Dec 24, 2014 at 21:10
  • I'm not doing anything with TRIM on it. The Mac Mini w/ SSD is heavily used every day. At this point, I'm just hoping that plenty of free space and the controller's garbage collection is sufficient to maintain performance Dec 25, 2014 at 22:12
  • Assuming you're using Yosemite in your Mini and wife's machine, otherwise Trim Enabler remains viable with kext signing intact. Apparently TRIM prevents write amplification even in Sandforce (OWC) SSDs. Cinder.org has something on this here.
    – thepen
    Jan 2, 2015 at 0:59

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