Yesterday I fell foul of this bug:
https://news.softpedia.com/news/how-to-fix-the-windows-10-activation-bug-523696.shtml Windows suddenly said it was not activated, and I actually had a Windows 10 Home license with Windows 10 Pro installed.
All I had done, was add a "K" drive mapping, so that my Kontakt library path could be the same between my desktop and laptop. However, it looks like Windows interpreted this as a major hardware change and deactivated my system... then the bug stopped me from re-activating, with the nonsense message about Windows 10 Home.
Luckily my previous backup was on Nov 4th, so I re-imaged my drive and got it working again.
The post above doesn't mention major hardware changes as being the cause of this bug, so I guess it's possible that this could happen for other reasons. It does say that it is happening to a lot of people though. I was waiting on the phone to Microsoft for around 20 mins, before eventually deciding to give up and re-image my drive.
So, if you've got a way of backing up an image of your drives - now's the time to do it!