Hi, I have mid 2012 macbook pro (OSX 10.10.1). Just bought my new Samsung 850 Pro 256gb SSD disc and whant to replace with existing. Tried out several methodes: 1) Cloning old hard drive to new - then I replaced it and I got flashing folder. Tried resting PRAM (cmd+option+P+R) - still the same. It did not eaven recognize it. 2) Then I tried to install from my OSX flash - opened Disk Utility - formated everything - Journaled + GUID. Tried to install, but at the last second I got - "Mac OS X cannot be installed on this computer" 3) Thought maybe the cable is broken, but when i recconect old hard drive, everyhting works perfectly. Just when I connect new one nothing works. If I connect my new SSD through USB I can boot it and everything works. Can anyone please help me ? One thing I noticed, that I am not really clear if that could be the issue - when I try to verify, it says that there is some king of EFI problem - could that be the issue ?