Apple kill third party SSD support in Yosemite In: Cameras Posted November 13, 2014 I have a mid 2012 Macbook Pro. I took out the stock HDD and replaced it with a Samsung 840 Pro 256 GB (also took out the Superdrive and replaced it with a hard drive caddy + 1 TB HDD). Ever since I did this I've always run the Trim Enabler app to patch OSX to allow trim support for the SSD. I've also had the app notify me if trim becomes disabled due to a software update so I can re-enable it. I updated to Yosemite few weeks after it came out and I didn't have any problem upgrading from Mavericks. Unless I just completely forgot, I don't recall opening Trim Enabler up and reverting back to stock settings without support for trim before I updated to Yosemite. I didn't encounter any boot issues. Once Yosemite was installed, I opened Trim Enabler and read about the kext signing and decided I would disable kext signing to regain trim support. I do realize if I ever have to do a PRAM reset I will have totally screwed myself and will be met with a boot problem and grey screen. Although I have read how to fix your system from the cindori.org FAQ on the issue. I don't really find it to be a big issue. I have a 3rd party SSD with trim support and everything works. It is a bit annoying that I have to turn of kext signing, which is sorta a security issue. I do agree though that Apple should have trim support for all SSD without the need for an app like Trim Enabler.