I restarted my MBP 15" early 2013 (running OSX 10.11.4) and the loading screen froze and displayed a long series of white text across the left side of the screen. I forced a shut down (by pressing and holding power button), waited a few mins and then turned it back on. It loaded fine, but I'm concerned what the frozen load screen was all about. Can anybody shed some light on this? Is my MBP screwed?