Can't Airplay Audio from MBA to ATV3. Ideas?

[JustGretchen]

I have a 2013 13" MBA running 10.9.1.
I have an ATV3, that I've just DFU restored (while troubleshooting this), on the latest ATV software.

When I attempt to airplay display to the ATV3 from my MBA, I get picture and no audio. Does anyone have any suggestions on other things to try. plists to trash, etc.?

Even going into the audio control panel and selecting the output source isn't working. See screenshot.

Thanks.

 

[JustGretchen]

I reset PRAM and gave the machine a cold boot and now it's working.

This makes no sense because it happens so often.