MS tried to do an automatic update - got an error. Now I’m dead in the water.
Google is your friend 
None of the “fixes” on Google work. Here is an example:
Dec 17, 2020 — It usually stems from not having enough storage space on your internal or external hard drive, so you could have ran out of space.
I have 300 free GB. Half of the replies are for XBox, I’m on PC.
I’ve tried everything that sounded reasonable. I’m really sick and tired of having these problems with FS 2020. None of the previous versions had these kinds of problems.