So it's seeing a valid first sector and enough of a partition table to identify the drive, but it can't find the volume header. That means that the auto-format routine failed in the very early stages. I second the suggestion to try wiping the drive. The short Write Zeros test in WD's Data Lifeguard Diagnostics is my tool of choice. In all my original testing, a Roamio would wipe any drive that it didn't recognize, but there have been some recent posts that suggest existing Windows or other partitions may screw up the auto-formatter these days.