Starting with SyncBackPro/SE V6.2, it is possible to backup and sync with hidden volumes that do not have a drive letter and are not mounted. To see which volumes are or are not mounted, and discover their unique Volume GUID, go to the command prompt and use the command mountvol

You will then see a list of all the volumes on the system and where they are mounted. The volume GUID's have the format \\?\Volume\{GUID}\

Use the volume GUID in the source/left or destination/right path in your profiles configuration like any other path, for example \\?\Volume{1962a3df-5101-11df-ae1d-806e6f6e6963}\My folder\Sub folder\