Yep, after having had El Capitan installed for a few weeks, recently updated to 'public beta 3', I decided to restart my MBP today, as it felt quite slow. My computer shuts off and when it attempts to start up again, a weird clicking noise begins, that I've never heard before. I am taken to a huge circle with a X in the middle (not referring to OSX), meaning the computer couldn't find a drive to boot up, all of a sudden. I panic, hard restart and hold CMD+R to repair the disk. IT'S ACTUALLY GONE. Just like that, for a simple restart, my hard drive completely crashed, and it is apparently irretrievable. I've got a TimeMachine back-up thankfully, but no disk to install it on. No disk to do a clean install of El Capitan/Yosemite with either. No external hard drives at my disposal either. Has this happened to anyone else? What do I do - take it to Apple's genius bar and pay the price (literally and figuratively) for signing up for the public beta? Is it fixable?