I recently bought a MacBook Pro Retina 15", the better of the two versions. Its operating system is MacOs Yosemite 10.10.1 - Sometimes I click to shut it down. While shutting down the screen becomes very dark, the mouse cursor remains active and white, and the keyboard is still enlightened. And it stays there. It doesn't switch off.! To switch it off I have to press the Power button continuously.! I don't know whether there is a connection to this problem, but today, I turned it on, and two user options appeared. The Administrator and Guest User. Never ever in the past did a Guest User option appeared. Over the next restarts it disappeared.! Is it normal? Could you please help me?