Here is a followup on backup. The Windows Complete PC Backup has worked well for recovering to an earlier time. Back2Normal has worked very well for recovering individual files and folders from backup, but I discovered that many Windows updates fail if I try to install them while Back2Normal is installed. Origin Storage is working on this problem. Meanwhile I am uninstalling Back2Normal after each use, and have changed my Windows Update settings to never install automatically, just download and inform me. After the problems I had with Windows file backup, I haven't tried to use it again.

By the way, I noticed that definition updates for Windows Defender are still getting installed automatically, and don't even wait for a check for updates. I wonder if this is right. Luckily these don't seem to be bothered by Back2Normal.