I have automated backups running on two different networks. One is writing to a removable SATA bay the other an external USB enclosure. All the backups (network and local) fail after swapping out the drives. The drive letter remains the same and I can restart the backups by using "Change Settings" which. Is there a way to correct this? Is Windows looking for more than just the drive letter?

This behavior is by design. If you would like to backup to different drive, you need to change the settings.Arthur Xie - MSFT