Please allow to use volume labels as much as drive letters

For the reason, please see https://forums.comodo.com/help-cb/drive-letters-changed-backup-does-not-get-executed-t52268.0.html.

If you use the computer management tool in windows to manually assign a drive letter that is not typically assigned automatically, the external drive will typically always use that letter when re-connected in the future. If that doesn’t work for some reason, you could use the tool mentioned in the other forum post USB Drive Letter Manager - USBDLM