I just got my rMBP yesterday (23rd), first power on to set up everything ran smoothly. I had to install an update though which required a restart, got to the log in screen after the restart then everything went black after I'd signed in, the screen was still on the though because the Apple logo was lit up. I forced a shut down and after that it turned on again and logged in smoothly. Now I've just started it up again and the same thing happened (inc. forcing shutting down then trying again). Any ideas? Should I just go and see a genius?