[MikeEm]

I think that my computer is hacked. Other software also appears altered on occasion and my antivirus recently caught malware related to bitcoin mining. Thank you for your help verifying that the backups are working. I will have to totally wipe the laptop and start over.

Alternatively you can turn Windows device into a Chromebook:
https://support.google.com/chromeosflex/answer/11552529
But you'd need an Android MobileSheets licence.

Thanks, I will definitely look into that.