Remove the duplicate drives by deleting them from the table Disk_Space.

You can use the drives letters identified in the Database_info column Filename to identify which drives to keep for the instance. For drives, that are not identified by a database file on them, keep the first and delete the rest. Sorry I do not have time to create any sample Delete SQL.

I have no experience with using mount points on windows. Maybe Microsoft's Doctor Scripto has an answer. Sorry