Same problem here. If I switch my denon receiver to PS3 and back to the HR34 it will show up. As the other poster said though, power up order and timing matters. The Harmony One remote I have is very powerful, but it is annoyingly difficult to get this right with one button startup. I tried for about an hour to get the stupid remote to do it automatically and couldn't do it. So I just switch inputs when it's greyed.