I was just installed yesterday, a new customer, with an HR21-100 which did an auto-upgrade to software 0x255 on installation. It is connected to a Sony 46W3000 via HDMI, the picture is fine. It is also connected directly HR21 to a Denon AVR1803 receiver via digital coax. The sound on the TV is turned off, the internal speakers disabled in favor of the home theater system. The same setup worked without issue with the TWC Moto DVR it replaced. The installer did not set DD on, so I went in and did. I had a good picture and good sound. The receiver showed DD as the sound source. Then it just stopped working within minutes, still a good picture but no sound at all on any HD channel with DD set to ON. The receiver no longer detects DD either, shows the incoming signal as PL II C, but normally plays whatever signal is fed to it automatically. It does not play any sound at this point though on any HD channel. I can drop down to the SD channel of the same broadcast and do have PL II C sound. I've tried multiple resets, both menu and red button. I've also tried turning DD OFF, saving it, backing out of the menu, then going back in and turning it back ON and saving it to no avail. The System Info shows DD as being set ON. The AVR receiver shows no detection of Dolby. This is brand new, 4 hours from installation that this bombed out on me and I am not a happy camper. It takes away from the HD experience. By the way, if I set DD to OFF, I do get sound on both the HD and SD versions of those same channels, both showing PL II C as the input. Why can't I get Dolby Digital as the input signal, it did do so for about 15 minutes?