All of our files have check marks when displayed on Windows Explorer (Windows 7, v6.1). Nice to know they've been checked, but how can we get rid of these icons?
If the checkmarks are a green circle, that is a Microsoft One Drive icon. If they are a green square at the lower left, that is a Norton Backup overlay, which you can disable in the Norton Backup settings.
https://support.norton.com/sp/en/us/home/current/solutions/v19829044_ns_backup_en_us