Hi there, Deadwood.
When performing a local backup in QuickBooks Desktop (QBDT) and the maximum number of files is reached, old files cannot be deleted automatically. Thus, you'll need to delete the files manually when the maximum number of backups is reached.
Moreover, if you encounter an issue while restoring your backup file, you can utilize this article for ideas on resolving it: Fix backup company file issues in QuickBooks Desktop.
Let us know if you have additional questions regarding backing up your company files in QBDT. We're always here to assist you.
