Apple’s Yosemite Beta: Don’t Use TRIM with SSD

| News

SSDFor those who are succeeding where others have failed at getting their hands on the public beta of Yosemite, make sure you disable TRIM before installing on a 3rd party solid state drives (SSDs). Users are reporting that having TRIM controls enabled will resort in your Mac not booting up.

A post over at Reddit reports the latest Yosemite beta (Public Beta 1, aka Developer Beta 4) is not loading modified kernel extensions (kext files). Since TRIM support involves modifying a kext file or two, if you leave it enabled, those kexts won't load, and now you're up to your knees in boot failure. That same post also outlines how to disable TRIM for the install and initial boot processes.

TRIM is a set of commands commonly used to communicate with the OS on a lower level, allowing the OS to better communicate free space and improve "garbage collection" on an SSD. Basically, over time, SSD performance will degrade without some sort of garbage collection, so TRIM keeps things nice and perky.

Image courtesy of Shutterstock.

The Mac Observer Spin The Mac Observer Spin is how we show you what our authors think about a news story at quick glance. Read More →

If you needed that third paragraph to understand what the first two were talking about, there's an excellent chance you should wait until Yosemite is available in the Mac App Store, sporting a "Now With Less Beta!" sticker. This kind of stuff is what beta testing is for, and when Apple says beta, the company means it. This is still software with a lot of kinks to work out, so if you do not crave adventure when opening apps on your production machine, maybe sit this round out.

Popular TMO Stories


Willy Pimentel

how do i know I am sing TRIM on my ssds?


Willy, look in System Profiler, under SATA/SATA Express.
It should show if TRIM is enabled.


Sidebar: If you are using an OWC SSD, you shouldn’t be using TRIM either, with any version of OS X. OWC’s firmware does a better job of garbage collection than OS X TRIM support.

Just sayin’.


Well , i installed it on a separate ssd partition and i found that it is very slowwww


Installed it on a second partition of my formerly Mavericks only HDD and imported data from that. Seems OK speed. A few things will need adjustments in GUI spacing. Personally I found my Printopia was not compatible and LetterOpener predictably was not compatible with the new Mail version. I have a OWC PCIe based SSD in there, so I guess +1 for iJack’s comment.

Log in to comment (TMO, Twitter or Facebook) or Register for a TMO account