I recently had a blue screen and evidently a corrupted windows 10 partition on my '13 RMBP. Instead of reinstalling win 10 I wiped the drive and installed win 8.1. Everything was going smoothly until I updated all drivers to the latest. I now get a restart loop just after logging in. I think I have narrowed it down to an external thunderbolt hard drive. I get the loop when it boots with it plugged in and no loop when it is unplugged. Anyone experience this?