What does my Yamaha A/V receiver automatically switch to the Audio input when I switch it to any of the HDMI inputs?

[TechnologyHatesMeButILoveIt]

I have never used an Audio cable to connect my receiver to my TV. I always use HDMIs so all of my devices have the best sound quality.Also its a 7.1 channel receiver and most Audio cables only support 5.1. Every time I switch it to an HDMI, it will automatic switch to Audio. It is very annoying because there is a five-ten second delay for when it does this, and it only does it 2/3 of the time. I can't just sit back and relax and watch a movie or play a game, because at any second the receiver could take my sound away. My remote doesn't really work well anymore, so I have to stand to change inputs. It gets very annoying after the 15th time in one day. And when it does this with my gaming computer it ends up messing up the auto completely and I have to unplug the receiver to get it to work again. (which is very hard to when it's plugged into a power strip -which is the only place it can be plugged in -behind a 30 pound entertainment unit.
This is not something that prevents me from using the receiver, but it is very troublesome and should not be happening. Is there any way to fix this?

The receiver is a Yamaha RX-V573

 

[americanaudiophile]

1. Try turning off the receiver CEC control function if it is on.
2. Some receivers will change to a different audio connection if the audio is lost in the HDMI. Make sure you have that HDMI input set correctly in the input set up menu and if you can turn off the auto detect try that too.
By the way coax and optical digital will all handle 7.1 channels but not in lossless audio codecs like Dolby True HD.
These are only available for BD discs so no loss of quality on other sources if you have to connect an audio cable (especially as a back up).