I've installed Parallels Desktop 12.1.2 as a trial on my existing boot camp partition running Win10. Things seemed to be working ok until Windows suggested that I update using Windows Update. I had an error message saying something like "prevent changes to master boot record" or some such. I'm now stuck in a reboot loop, where the error message is "CRITICAL_PROCESS_DIED", and all attempts to repair Windows fails. I've sent the error report using the "Send technical data" in the app, but no answer.