Hi there, It's almost all in my title, but here is a bit more explanations. I bought a new Samsung 840 evo drive (500G) and an adaptor to put it in my drive bay. I now have my original 500G HD and the 500G SSD. I successfully installed Yosemite on my SSD, but when I restart, I have "the" sign (round with a bar), and my computer boots on the HDD. I restared a few time in debug mode and reselected the SSD as a startup disc, but it always does the same thing. My first try was by cloning my HDD to my SDD, then I did a clean install from a memory stick, still the same result. I am reading a lot of things about Yosemite and SSD's, but since I never used a program to enable TRIM I should be be concerned right? My next move might be to swap my HDD and my SSD, but I would like some advice first and know if that will help in any way... My MBP is an early 2011 one. Thanks for your help!