AFAIK no WD My Book eSATA drive is compatible with TiVo. In other words, they just don't work (something to do with the My Book enclosure/bridge, etc.) This statement in the FAQ is still correct: As bkdtv mentioned, If you have a TiVo HD you would need to open it up, pull the internal hard drive and marry any eSATA drive but a WD My DVR Expander for it to work. If you don't want to use a My DVR Expander the common practice is to simply replace the internal hard drive since you have to open it up, pull the drive and connect it to a computer anyway. Put the original drive on the shelf as a backup and you're in business. Happy upgrading!