Hi all, I currently have a late 2011 15" (i7 - 16GB ram) Macbook Pro. I purchased a Kingston V300 Series 240GB SATA III drive to put into my laptop; I put the HDD where the optical drive was, and the SSD where the HDD used to be. The problem I'm having is that my laptop won't recognize the SSD - it would show up once and awhile and then disappear again. Only drive listed in disk utility is the basic 750GB "Macintosh HD". I took it to my local Apple Re-seller that does repairs, and the service tech said that SATA III is actually too fast for my mac, and it "just happens sometimes". He suggested I put a SATA II drive in, which to my knowledge is somewhat hard to find nowadays. Does this sound right? and if not; any ideas? Thanks! I appreciate any input.