Advertisements I purchased a My Book AV DVR Expander a couple of years back and happily used it with an RCN Premeire Tivo box. After a move, I was without a Tivo, and due to a hard drive failure I was also without a backup drive for my computers at the same time, so I took the unused My Book and reformatted it to perform back up duties. Well, I'm back in the Tivo fold with a Roamio and wondering if I were to plug the My Book in to the Roamio Sata port, would Tivo reformat it for it's own use again? I will probably just try this, but wondered if anyone had any experience to share. Thanks!