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Sep 21, 2012
In the middle of several books.
Here is a simple work-around to get DiskSensei working (from site) I tested and it worked. No gray screen. I checked "About this Mac" and TRIM shows enabled.

Note: If you have existing boot-args, you need to adapt commands below accordingly (or they will be removed!).

1. In Terminal:

sudo nvram boot-args=rootless=0

2. Reboot
3. Enable Trim with Trim Enabler/Disk Sensei
4. In Terminal:

sudo nvram -d boot-args

5. Reboot

Done! You now have Trim enabled with 100% of OS X security intact, and will not risk any gray boot screen issues.


macrumors 601
Mar 6, 2013
Charlotte, NC
Thanks BGG, that actually sounds simpler than the previous method of dealing with Dev mode. I'll try this out in a bit and see what happens.

Since Dev mode isn't an issue here, can I assume that once it's all done, PRAM resets won't be a issue for TRIM?


Sep 21, 2012
In the middle of several books.
If accurate, that just deflated my happiness with having TRIM and (hopefully soon) Continuity running El Capitan (via kext hack for upgraded BTLE card).

Stay with El Capitan with better performance and security, or go back to Yosemite with the aforementioned benefits, and not as good on performance and security compared to El Capitan?

Decisions to be made.


macrumors 6502
Jun 24, 2010
it would be nice if it was included... but if not, why not just use something like the app "Trim Enabler" like i use now. seems to be working well.


macrumors 6502
Apr 11, 2013
Not tried it on a real Mac, but the classic manual binmod of the IOAHCIBlockStorage binay file (inside the IOAHCIBlockStorage PlugIn kext of IOAHCIFamily kext) does work in 10.11 just as it did for any other previous OS X version.

-> Using any Hex editor (such as 0xED for instance), look for the 1st instance of "APPLE SSD" and replace:
00 41 50 50 4C 45 20 53 53 44 00 (="APPLE SSD" in ASCII)
00 00 00 00 00 00 00 00 00 00 00 (=empty character string)

Save the modded file, replace the original binary file in the kext, repair permissions and off you go with Trim enabled.
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Oct 21, 2009
Honestly, it is not worth it dealing with TRIM. I have a 2010 Mac Pro and have used SSDs without TRIM for years without any issues or slowdowns.

They should remove the option to disable kext signing. If we can do it, malware can do it.


macrumors 6502
Oct 29, 2010
Guys, there is a native way, now. Just enter "sudo trimforce enable" in Terminal.

Edit: Well, it's not yet working correctly, but I guess it will eventually.

Edit2: okay: try this:

1. Disable Rootless (sudo nvram boot-args=rootless=0)
2. Run "sudo trimforce enable" read it's text and do what it asks you for.
3. Enable Rootless again (sudo nvram -d boot-args)
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macrumors 68000
Aug 13, 2009
holy sh*t. indeed there's /usr/bin/trimforce. in it it says:

This tool force-enables TRIM for all relevant attached devices, even though
they have not been validated for data integrity while using that functionality.
By using this tool to enable TRIM, you agree that Apple is not liable for any
consequences that may result, including but not limited to data loss
or corruption.


macrumors 68000
Aug 13, 2009
it works!!! TRIM is enabled now :cool:

Screen Shot 2015-06-12 at 14.36.57.png


macrumors 6502a
Jul 7, 2012
Your wrong, my friend, all SSDs need Trim as has been established on this forum time and time again. If Trim Enabler is enabled and you do something that involves changing the kexts, your in big trouble. Do some reading and you'll see why.

Happened to me not 3 days ago. Needed to boot into safe-mode to fix Apparently, I should've turned off Trim Enabler before doing that - something I obviously neglected to do.

Was met with the grey no-entry sign on reboot. Several hours later, after unsuccessfully trying the recommended Terminal commands, I managed to get my OS reinstalled (Yosemite) - thankfully without losing anything. Haven't enabled Trim again - don't think I will, either. Too much of a PITA.


Sep 21, 2012
In the middle of several books.
Does this allow to re-enable Rootless after change has been made?

I did notice last night, that when I tried to turn Disk Sensei off in the app, it wouldn't allow me to toggle to the off position. And when I tried it, I would get the please restart your computer message, as if it had worked. Rebooting the computer still showed it as enabled.

Can someone else try this and see if you get the same results? I am wondering if rootless needs to be turned back off, in order to turn off TRIM in the app.


macrumors 603
Aug 6, 2007
timsutton said:
Apple engineers have confirmed that the nvram boot-args command option will not be in the shipping release of El Capitan, and may be removed from developer betas before the release.

If this sticks, I'll hang in with Yosemite for a while and then who knows. Take a good long look back at win 10 maybe. Apple's f'in with us now. . . biting the hand may backfire. Then again, the legions of apple zombies will no doubt follow along like robots... In any case I am very disappointed in the direction Apple is taking with OSX. Marketing wise, I do realize that us tinkerers and power users are 100% expendable from Apple without really affecting their bottom line very much. But we can make some noise if it does end up too onerous. . . . sigh . .
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Jul 1, 2011
It sounds like rootless may have actually HELPED the TRIM setting issue rather than making it harder. :)

So this and the previous posts suggest that disabling kernel signing is not required anymore when disabling rootless?

And people claim TRIM support is still working when you re-enable rootless AND disable developer mode again (-> kernel signature check re-enabled)?! That comes as a bit of surprise, and if that's the case, I guess that's really a bug and will be fixed in the release version.

Or does the OS really not bother anymore to verify kernel extension signatures - at least the extensions it "knows" are from Apple - when rootless is enabled, under the assumption that "they couldn't have changed anyway"?

Somehow I don't think that will remain forever - that sounds like a bug to me...
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