I've been worrying away at this thing for a while. Can someone help me out? I purchased a 256GB Samsung 840 Pro SSD and put it in my MBP 15" Late 2011 I Installed Linux without issue on this, used it for a few days (no issues) then decided to switch back to OSX Snow Leopard. Install disk for Snow Leopard will NOT install when SSD is in (3-beep failure on booting from disc) Installed OSX Snow Leopard on the SSD via USB from an iMac, put it into the MBP and boom, three-beep error. Using my regular stock disk, I can boot fine with the exact same configuration. I have reset NVRAM and SMC and all my firmware on the MBP is up-to-date. While the 3-beep error usually means "POST failure, No Good RAM Banks" this is not actually the case, as I have tested the RAM using my stock hard drive. TL; DR -- Linux works fine on my new SSD, but OSX Snow Leopard refuses to install or boot from the SSD. Did I miss something or is the SSD incompatible with Snow Leopard?