I just bought a new 13" Macbook Pro Retina. Whenever it is connected to my 27" Apple LED display and I restart the computer, it won't start back up. I hear the chime, then everything just stays black for about 30 seconds, then I hear the chime again. It does this over and over...it just keeps restarting. When it's not connected to the Apple display it restarts just fine and boots up. I'm running Yosemite and not sure if this might be a bug. Does anyone else have this problem or have any suggestions to fix it? It's annoying when I have to disconnect from the monitor every time I just want to restart the computer. Thanks in advance!