That makes total sense. Thank you. I couldn't find anything else about it anywhere. I finally restarted the computer and it went back to normal.
I had another odd thing happen. I was doing a manual backup and found some folders on the desktop empty of files. Luckily what was in the folders was old stuff I only save for record-keeping and was still in my last backup. But, I know I did not delete those files and absolutely no one else has access to my computer except possibly the cat. I just woke up and decided I may as well run a full virus scan while I am trying to go back to sleep.
I may as well mention this...I also have Carbonite backup. I'm a writer with several manuscripts on my computer and a photographers with thousands of pictures. One physical backup is not enough. The last two days, the Carbonite interface shows that I have fewer files backed up than I did. I have not removed anything from my Carbonite account, nothing shows as missing or not backed up on my computer--except the things I put back tonight--and Carbonite insists they have no way of telling if the account was accessed and anything deleted. I have changed my password.
This has all happened since the last round of Windows updates. It kind of makes me want to email my ex husband and tell him thank you for drilling it into my head to always have three backups (he's a network and systems technician).