WHy does this constantly happen ? In OS X Mountain Lion, (especially when booting from the Recovery Partition for example), sometimes the Mac goes to sleep, but when you wake it up. the screen disapley is still black. everything is unresponsive, even the keyboard, although the sleep indictator is not pulsing/on at all. The trackpad does not operate, nor does the Caps Lock key see any reponsive Led Since you can't see anything, you only option would be to power off/power on. This has happened more than once on my 2012-MBP.. even SMC reset din't help. This is alsp fatel during a write action taking place.