Hi! I am a user of 15" Macbook Pro retina early 2013 and since the beginning one issue is still causing me problems :/ when I close the macbook while running, it normally enters the sleep mode. But after waking it up from sleep, I can see a black area covering large part of the system. What I have to do is enter a screen saver (using active corner) and then turn off the screen saver . Then I can see everything properly. Any idea what may be causing this? Thank you! See the attached screenshot.
