I have a 3TB WD My Book external drive that I use as my primary backup target. A few months ago I purchase a 2TB My Passbook external drive to store all my pics and home movies. Before I purchased the Passbook I used an external drive of another brand to store my pics and videos. This external drive was then backed up to the My Book with no issues. Now the WD SmartWare software identifies the Passport as a backup target and therefore will not let me use it as a backup source to the My Book. Therefore I haven’t been able to automatically backup the My Passport. Is there a way for the WD SmartWare software to recognize the Passport as a backup source?
Try to uninstall and reinstall the smartware software on the computer see if that helps.