Originally Posted by steve614
WD makes different versions of the "My Book" external hard drive. You want to find the one that specifically mentions that it works with Tivos.
I believe it is called the My Book DVR Expander.
I think there are actually at least two versions of the 1TB My Book DVR Expander, only one of which is certified to work with the TiVo.
The other one is for somebody else's DVR.
As for the OP's question, if they're looking for an external drive (better to replace the internal with a bigger one), then they have to find the one with the TiVo logo on the box.
No TiVo logo, it's not on the very small list the TiVo checks external drives against.