I installed the My DVR Expander when I installed the TiVoHD, last October. It had been working fine, and still recorded SD programs without a hitch. I did the TiVo tech troubleshooting and somehow didn't find the problem. Then, after much thought, I tried doing a much more complete uninstallation of the Expander drive, since it was now attached to the brand spanking new HDTiVo, and therefore, pretty much empty. As I recall when I troubleshot with TiVo on the line, I never lost anything from the Expander. While this seemed marvelous at the time, I see how improper it was now. So in the process I disconnected the Expander from the TiVo and restarted it and ran it without the Expander and it ran beautifully. Hmm, I says, this would seem to indicate an Expander HDD problem. I plugged it in again and set it up and the HDTiVo ran as screwey as before. I immediately jumped on the Western Digital page and typed in the serial number of my Expander, it was still within the guarantee period and I arranged for an RMA swap and they sent me another Expander and it has been working as advertised. I don't know what the problem with the original drive was, but I used my original eSATA cord with the new drive, so that wasn't the problem. The interesting bit is that when I called TiVo to tell them that I had it all figured out, I told them that I had purchased the Expander from them and I wanted another one, the rep advised me to hold on and he was going to check on that, then they disconnected. I haven't even called them back as I had already done the RMA with WD. I thought it was interesting that they didn't immediately shut me down on the Expander RMA question. I thought I had read here that they don't service the My DVR Expander, maybe they do.