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Enable TRIM in OS X 10.7.5 to 10.9.5

Enable TRIM on non-Apple SSDs in OS X

NOTE: This is tested on the versions mentioned in the title, and NOT earlier or later versions. YMMV.

Run the following commands in Terminal…

Backup the original driver:

sudo cp /System/Library/Extensions/IOAHCIFamily.kext/Contents/PlugIns/IOAHCIBlockStorage.kext/Contents/MacOS/IOAHCIBlockStorage /System/Library/Extensions/IOAHCIFamily.kext/Contents/PlugIns/IOAHCIBlockStorage.kext/Contents/MacOS/IOAHCIBlockStorage-backup

Modify the driver (choose only one of the following lines, based on the version):

# 10.9.4 & 10.9.5
sudo perl -pi -e 's|(^\x00{1,20})[^\x00]{9}(\x00{1,20}\x54)|$1\x00\x00\x00\x00\x00\x00\x00\x00\x00$2|sg' /System/Library/Extensions/IOAHCIFamily.kext/Contents/PlugIns/IOAHCIBlockStorage.kext/Contents/MacOS/IOAHCIBlockStorage

# 10.8.3 to 10.9.3
sudo perl -pi -e 's|(\x52\x6F\x74\x61\x74\x69\x6F\x6E\x61\x6C\x00{1,20})[^\x00]{9}(\x00{1,20}\x54)|$1\x00\x00\x00\x00\x00\x00\x00\x00\x00$2|sg' /System/Library/Extensions/IOAHCIFamily.kext/Contents/PlugIns/IOAHCIBlockStorage.kext/Contents/MacOS/IOAHCIBlockStorage

# 10.7.5, 10.8.1, 10.8.2
sudo perl -pi -e 's|(\x52\x6F\x74\x61\x74\x69\x6F\x6E\x61\x6C\x00{1,20})[^\x00]{9}(\x00{1,20}\x4D)|$1\x00\x00\x00\x00\x00\x00\x00\x00\x00$2|sg' /System/Library/Extensions/IOAHCIFamily.kext/Contents/PlugIns/IOAHCIBlockStorage.kext/Contents/MacOS/IOAHCIBlockStorage

Run these commands in succession to clear the system caches to enable OS X to pick up the modified driver:

sudo kextcache -system-prelinked-kernel
sudo kextcache -system-caches
sudo touch /System/Library/Extensions/

Restart the Mac.

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Looks like Apple's playing cat and mouse with this one. Maybe it's ANOTHER coincidence but this workaround isn't working on the first 10.8.3 prerelease (12D32).

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Doesn't work on 10.8.2 12C3006 (MacBookPro9,2 = 13" Mid-2012) :(

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got this: Kernel file /mach_kernel does not contain requested arch: i386
after running this: sudo kextcache -system-prelinked-kernel

mid 2012 2.3 mbp 15" 9,1 on 10.8.2[12C60]

"TRIM Support: Yes"

SUCCESS! Thanks!

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It Works.
Thanks a lot.

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I've tried a similar command line on 10.8.2 but for 10.6 on iMac27 2011. Result: The reboot never ends ... I get the apple logo with the rotating clock ticks, then the apple logo become a round with an oblique bar in it (similar to a disable icon) with a never ending rotating clock ticks. I do I revert back to the original file as I do not get access to finder anymore. Thanks for your help.

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DennisNg commented Feb 9, 2013

First thanks for the patch for 10.8.2.

I did a backup first then follow yours.

Based on another web site, I add another step after your patch which I am not sure it is important:

  • sudo touch /System/Library/Extensions/

Also, after the command "sudo kextcache -system-prelinked-kernel"

I got some system messages:

/ locked; waiting for lock.
Lock acquired; proceeding.
Kernel file /mach_kernel does not contain requested arch: i386

But ignore it and continue with the "sudo kextcache -system-caches" and reboot; the Apple did report Trim Support.

Hence, may be everything is ok.

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Thanks a lot! I did not have success using Groths Trim Enabler with 2012 MacBook Pro with Mountain Lion 10.8.2 and a Samsung SSD 840 Pro 512 GB. In addititon I got some system crashes after I tried to activate TRIM using the TRIM Enabler. I never saw this befor (!). TRIM could no be enabled.

Thanks to your lines I had success within the first attempt.

Jochen, Berlin, Germany

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gbdoin commented Feb 26, 2013

Not working for me on 10.8.2 MacbookPro 13" mid 2012 with Samsung 128 GB 840 pro series. If somebody had the same problem and found a fix, please share :)

Edit: leolimajr's Fork worked for me, thx man! :D

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orion11 commented Mar 3, 2013

Worked for me. 10.8.2 ( 12C60 ) early 2011 Macbook pro 13" , IOAHCIBlockStorage version 2.2.2 , Samsung 256 gb 840 pro. system information shows Trim Support: yes now :) Thanks!

note: did the extra "touch /System/Library/Extensions/" step thats DennisNg mentioned and is in leolimajr's fork, just cuz.

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vgorloff commented Mar 6, 2013

Thanks! Working for me too. 10.8.2 ( 12C60 ) MacMini Mid 2010 with Crucial M4 (CT128M4SSD1).

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iCrunch commented Mar 15, 2013

Hey guys! 10.8.3 just dropped (build 12D78). I have an Intel 520 Series 240GB in a Mac mini (6,2) and TIM is, of course, disabled. I was about to try one of the 10.8.2 "hacks", but then I noticed one poster saying "this is only guaranteed on 10.8.2, not before, not after", so I'm holding off for now.

Any news would be highly appreciated!

(Btw, if you don't have TRIM going for a while and then turn it on, will it "undo the damage" that NOT running TRIM until that point caused? Dramatic, I know. But curious. Always curious. ;-) )


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skomik commented Mar 15, 2013

Didn't work for me on MBP 2011, OSX 10.8.3 (12D78). Waiting for update =)

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My fork is still working on OSX 10.8.3 (12D78) take a look at

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Updated the gist with the "sudo touch /System/Library/Extensions/" command.

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xplainit commented Sep 5, 2014

OSX 10.7.5 build 11G63.
Trim ENABLED. Thanks a lot !!!

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bizulk commented Nov 3, 2014

MBP With OS X 10.9.5 (13F34)
==> WORKED 😄
Question : How did you find out ?

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Worked in MBP with OSC 10.8.5

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MacBook 2.1 2007 upgraded Tiger --> Snow Leopard --> Lion 10.7.5

It worked like a charm first time!

Thank you!!!!!!!!

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Bammonb commented Jul 21, 2015

Hello All,

Thanks for taking the time to post this information.

Unfortunately I feel that enabling TRIM on my Kingston SSD has slowed it down.

It did enable TRIM successfully.

What is the best course of action to reverse these changes?

I am running MAC OSX 10.9.5

Do I need to go to Genius bar and have them drop a new Image on the HD?



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fefone commented Dec 26, 2015

successfully enabled TRIM on MacBookPro6,2 - OS X 10.8.5 (12F2560) for a Samsung 850PRO.
Thanks a lot!

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Thank you. This help me with a MacBook late 2007 model running OS X Lion on Patriot Pyro SSD.


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Thank you it works like a charm on a 10.9.5 But if System Information says Trimm is on. Is it really on? How can I see that this is on. And by the way what does it? Randomly change the Memory Location of every bit?

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RJVB commented Apr 21, 2020

Exactly where am I supposed to see the trim enabled indicator on OS X 10.9.5?

I think I've applied the correct patch from the list above but I cannot seem to find the indicator for my external Kingston SUV500MS120G (SSDNow family).

> md5sum /System/Library/Extensions/IOAHCIFamily.kext/Contents/PlugIns/IOAHCIBlockStorage.kext/Contents/MacOS/*
79f51aaf114f3dd8be5e409f6e3c13df  /System/Library/Extensions/IOAHCIFamily.kext/Contents/PlugIns/IOAHCIBlockStorage.kext/Contents/MacOS/IOAHCIBlockStorage
ef72c0c2bfb1074bf400d3405efdae10  /System/Library/Extensions/IOAHCIFamily.kext/Contents/PlugIns/IOAHCIBlockStorage.kext/Contents/MacOS/IOAHCIBlockStorage-backup

> kextstat | fgrep -i IOAHCIBlockStorage
   61    0 0xffffff7f813bb000 0x18000    0x18000 (2.6.0) <43 16 6 5 4 3 1>

contents comparison, does this look correct?

> od -x IOAHCIBlockStorage-backup > /tmp/kk1
> od -x IOAHCIBlockStorage > /tmp/kk2
> diff tmp/kk[12]
< 0201720      0a79    4100    5050    454c    5320    4453    5400    6d69
> 0201720      0a79    0000    0000    0000    0000    0000    5400    6d69

EDIT: I just realised this patch replaces the string "APPLE SSD" with as many null bytes. I see a second occurrence of a very similar pattern a bit further in the file: "APPLE SSD TS". I guess I have nothing to lose to replace that one too (would I have an older version of the framework on my system?!)

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@RJVB You should be able to see it in System → Hardware → SATA → Trim Support: Yes

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RJVB commented Apr 26, 2020 via email

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@RJVB I've only tested this on SATA SSDs, as this was the only way to get TRIM back in the day. (Later versions of OS X supported the trimforce command.) Sorry, I don't know of a way to check if TRIM is actually working at a lower level.

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RJVB commented Apr 26, 2020 via email

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Thanks man. Worked on my evo860 SSD on my mid-2012 i5 on OSX 10.9.5 after the initial software update following reinstallation of OS X.

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Hi there — Can confirm this code works on 2006 MacBook Pro 17" Core2Duo 3GB RAM with cheap Fanxiang S101 1TB SSD.

Had to paste into Terminal a couple of times, reboot, no joy in System Info — so tried final time but pasted all three of the second set all at once — rebooted again and System Info confirmed "Trim Enabled: Yes". Thank you so much! Very pleased.

Thanks for figuring this out.

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P.S.: That's on Mac OS X 10.7.5. Lion (!). Works like a charm.

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