It could be the enclosure. I've found Vantec enclosures to be hit and miss. USB2 models seem to work the best with PVRs. I've had issues with USB3 models or those with both eSATA and USB2. Even the colour of the case can make a difference as that seems to indicate various internal hardware revisions. I had two cases with the same model number. The black one worked and the blue one didn't.