Updated to 1903 but 'user'.000 now created and holds all my user files

This might not work for everyone, but I had this problem too, and was able to "fix" it.

I saw that the newly created second username folder only had a few files in it, belonging to Zune. Just as an experiment, I did 2 things:

Firstly, I rolled back windows, and then uninstalled Zune, and removed any old Zune file/folder I could get to (a lot of old Zune files are out of reach because Windows won't let you in those folders), and then restarted my computer freshly.

Secondly, I also unplugged my external hard drives, because someone from Windows had this mentioned in a list of actions I could do, and this was a simple thing to try, so that is why I did it.

Then I let Windows download and install the update (which was now called 1909 for some reason, in stead of 1903), and it worked. I had my normal username folder, and no .000 folder.

So I am not sure which was the exact fix. I remember though that it happened before that Windows 10 updates had problems when hard drives were plugged in, so this could very well be the issue again.

I repaired the damage and continued to use the .000 profile. The only other alternative is to revert back to the previous version before it is too late. Remove Zune. Reinstall 1903.

I spent several hours on the phone with Level 3 MS tech support, and got no solution. I tried to make it work, but Dropbox was a hopeless tangle, and I could not get it to work correctly with the .000 user profile, nor would Outlook work even after I redirected it to the new data file location. I decided to roll back to ver. 1803 -- again -- but that was only partially successful.

I am now waiting for a full restore from disk image to complete, and then I am going to try to disable Windows updates in the Services sections and stay with 1803 for as long as my computer lasts, or until I have a week of spare time available to do a clean install of the update and rebuild my platform from the ground up. (Not likely to happen.)

I am really tired of the shoddy engineering and testing that leads to these situations.