Hey Friends! I recently was able to successfully save my old HD Tivo with a new drive replacement because of the help of this forum. Thank you so much! That being said, I was curious, I read on another thread that If you upgrade the internal drive of the Tivo, the 'Plug&Play" external drive add on would no longer be possible. I still have a WD My Book AV external hd that was attached to the unit before the internal upgrade and would love to still use it if possible. I was curious; Why wouldn't it be able to be used after an internal drive upgrade? Thanks!