Yep! It happened!
I always avoid Windows feature updates until they have been around for many months and most of the glitches have been sorted out. Last night, in a distracted moment, we told Microsoft to go ahead and install their latest features update. The result - a completely corrupted operating system on my better half's PC. Trying every recovery trick I know, and a few that I learned from Dr Google in the early hours of the morning, I failed to fix it. This morning saw me very reluctantly clicking on the instruction to completely wipe the hard drive and reinstall Windows. It didn't go smoothly, of course, but I am pleased to report that I actually got to speak to a human being in Microsoft who was very apologetic and was very helpful. We back up regularly so we haven't lost any data files BUT we have lost about 12 months of emails and two days of my life, because I still have much to do and it will take me all day tomorrow as well to get the PC back to where it was pre-nightmare.
The moral of the story is don't download and install Windows 10 20H2 until Microsoft doesn't give you a choice. It is bad news!