After using an external monitor with my macbook, I get a black square on my macbook once it's disconnected.
I've attached an image to show what's going on. In subtext: I use my macbook as a notebook for work away from my apartment. However, when at home, I connect my macbook to an external monitor and leave it close. Essentially, I use the macbook as a hard-drive. But now, once I disconnect from the external monitor and open the screen, I get this blank screen. It only goes away once I restart/shutdown my macbookpro.