Have used the product successfully many times from a int 2tb to a wd 2tb ext for backup.
Just bought 2 3tb WD Mybooks.
Fbackup sees both drives but when I pick drive 1 s: folders for source and tell it to go to the drive 2 t: it accepts them both as source and destination. But soon as I exit the advanced settings, it displays the source drive as also the destination. Cannot get it to take the 2nd drive.
I did have to enable the 2nd drive via windows management as the 2nd one once installed came up with a duplicate ID. Figuring this might be the issue with FBackup but once I enabled the 2nd drive, it works fine. Can manually copy files no issue.