I have a XL4 using Comcast Cable. I recently installed Tivo Desktop to my new Windows 8 laptop and transferred a 4 hour program. The video transferred fine, but I didn't have sound. Then, I found a post here that gave me a link to a codec at C-Net. I downloaded that and got sound. A few days later, I added the recommended WD 1TB Expander to my DVR. Now, I'm getting "Tivo Desktop did not find a Tivo DVR on your home network." I can't transfer new programs nor see the previously transferred program on my DVR/ TV. Does the downloaded codec or addition of the Expander have anything to do with this problem? If so, can it be resolved? Or is something else causing this problem and can it be resolved?