Probably one of the worst mis-features of modern Windows is automatic rebooting to install updates. This means that you cannot trust Windows not to restart. Whether it is due to a blue screen of death, or Windows updates, an automatic reboot means that whatever was running is lost. It means that you can't set it running a long job and expect that, aside from an actual system crash, the system will dutifully get on with the job. I like to use a PC as an alarm clock, waking at 6am and starting VLC playing.
There are many articles on how to disable this. I'm not sure if any work.