I just installed a new 850 Evo 500 GB ssd into my macbook pro. I cloned the original hdd onto the new ssd and was able to boot while the ssd is plugged into the usb port. When I tried to install the SSD into the old hdd position using the SATA (I believe SATA II) cable it would not boot. It just loads about halfway through the bar on the apple screen and just sits there. I took it back out and plugged it in via usb and it is running fine. I have heard that there might be a need to switch out the SATA cable for a new one that is for SATA III (original HDD works fine with the current cable). Anyone have similar issues or any corrections?