andreamz on "Archive Cleanup not working for Mapped drive"

I have IDrive 6.5.1.0 running on Windows 10 x64, all current updates installed.
I backup files from my local drives, from an external USB drive and from a Network drive (I think IDrive calls that a Mapped drive). All the backups work fine, but the Archive Cleanup does not work for the Mapped drive: if I run it from the IDrive desktop and select “consider 100% of files for cleanup” I get back the popup “There are no items to delete” even though there are multiple files that should be deleted for the Mapped drive. The other drives on the other hand seem to be cleaned correctly.
Any suggestion?
Thanks