I had issues with my HR20 so DTV swapped it out for a refurbished HR21. During setup I noticed the Dolby Digital setting and turned it on. Now I am experiencing problems with Dolby Digital audio dropping on my Denon AVR-2800 when I press a DVR control button i.e. rewind, fast-forward, skip-forward, etc. I do not experience any problems with analog audio. I do not remember if the HR20 had this feature or if I had it turned on. DTV sent out a technician who swapped the HR21 for a brand new HR22 but it has the same problem. The technician had no idea what might be wrong. I am using the optical cable connection for digital audio. I have tried two other optical cables, all three optical ports on the Denon and coax, but it did not remedy the problem. These same three cables and ports work flawlessly with my DVD. It seems to me as the audio signal is being interrupted from the HD DVR to the AVR-2800 when I press a DVR button and the receiver is unable to reestablish the connection. The Denon has a ‘lock’ light that goes out when the audio is lost. If I change to a SD channel the Dolby Digital audio is reestablished again. Unplugging then plugging in the optical cable also reestablishes the audio. The Dolby Digital audio works fine for as long as I do not press a DVR control button. This is a very frustrating problem since this problem defeats the purpose of a DVR. I don't think there are any settings that I can change on my AVR-2800 to help prevent this problem. I normally use the "Auto" setting where the receiver detects the input signal. I have also tried ‘Direct’ and ‘Pro Logic’ settings but all fail. Does anyone out there have an idea why my receiver loses the Dolby Digital audio? I have found one other person on a forum with the same receiver and problem, 100% match, but no resolution.