Yesterday I connected my 2011 15" MBP to my 27" monitor, connected a new portable hard drive to the USB port on the back of the monitor, and backed up with Time Machine. When i put the computer to sleep and disconnected it and than opened it, I got a blue screen that i could see thru (should say translucent instead of transparent). I could not get a normal screen until I restarted the computer. I tried it a couple more times with the same results. I found another person on the Apple forum with the same experience, but there were no responses to his query. After I restored the hard drive with my Super Duper backup from the day before, I never had the problem again. Has anyone experienced this or do you have any idea what could have caused it? Thanks for any responses.