ATI HDMI Audio disappears in Windows 7 when a TV is connected

"I solved it!

You need to unplug the HDMI cable before you do this because the driver doesn't show up in the list if you don't.

If you locate the driver in ""Properties"", right click the speaker down by the clock on your desktop toolbar. Select ""Playback Devices"". There you should have the ""Digital audio (HDMI)"" icon.
Click it and select ""Properties"" at the next window. Again, select ""Properties"". Now you get to yet another window.
At the bottom left corner there's a button that says, ""Change Settings"". Click it and if UAC needs permission, then allow it. OK, another window, klick the ""Driver"" tab, here you should click the ""Rollback Driver"" button.
And when it is done, voila: HDMI sound again!

Long description, short fix: You can access this exact driver from Windows Device Manager too if you know which one it is.

So, now you can forget about getting those extra cables and rebooting your machine every time you want to use your HDMI output

My specs: Packard Bell laptop, ATI RADEON 4570 Chipset, Latest reference drivers from amd.com, Windows 7 Home Professional 32bit"

"I ran into the same issue when I connected a settop box through my AV receiver: when somebody had watched TV, the HTPC had lost its HDMI audio and instead I got a message that an SPDIF connection was detected. Rebooting indeed solved the issue, but only until someone turned on the settop box again.

On another forum (can't recall the name) I found the suggestion to disable the AMD External Events Utility in msconfig, which indeed seems to work for me until now and which also makes sense I think.
So have a try if this helps? And if it does, credits to the other guy of course.."