'MS-Access problem with database when I try to back up or Compact & Repair

I have an MS-Access database I have used for 10+ years and I daily Compact & Repair and then BackUp. Today it failed saying 'You attempted to open a database that is already opened.... etc..'. So, tried a backup - same message, couldn't even close MS-Access - had to delete via Task Manager. Tried a reboot, same result. Tried opening several of my daily backups but they all gave the same result. Went to Settings/Apps and Repaired 365. Tried again, same result. Can anyone suggest anything please?



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