I was listening to music and doing some heavy research online (clicking through many websites) when all of a sudden my MBP froze and the screen turned dark with vertical red lines. I had to shut it down manually. When I restarted it, all I could see was gray screen and after a couple of mins appeared a flashing gray question mark. I tried safe-booting from my USB and opened Disk Utility and it wouldn't show my SSD.... Which means......that my Crucial M4 failed? ****UPDATE**** After performing a "power cycle", my SSD is alive and kicking! Really glad it was just that and not actually dying. Performing a power cycle is a fairly easy process. All you need to do is the following: 1. Shut down your Macbook. 2. Plug it in electricity, turn it on and leave it alone for 20 mins while the gray folder with the question mark is flashing. 3. Shut down your Macbook. 4. Unscrew the back of your Macbook and disconnect your SSD from the SATA cable for 30 secs. 5. Connect it back to the SATA cable, put the back plate of your Macbook back on and turn on the Macbook. 6. It booted again for me. Also, I updated my SSD firmware from 010G to 070H just to be on the safe side. I hope I won't ever have to do the power cycle again.