This "correct answer" doesn't address the problem. I understand that the NUC doesn't have an onboard audio device. It passes audio via HDMI to, in this case, a receiver. When the receiver is turned on and the NUC is booted, the receiver is recognized. When the receiver is off and the NUC is booted, no audio device is recognized. This also makes sense because if the receiver is off, there's nothing to pass audio to.
The problem is that when the NUC is sitting in Windows 8 (in my case), I turn off the receiver, then turn it back on later, the sound doesn't come back. The NUC can't "handshake" once again with the receiver unless I reboot the NUC.
If I boot my NUC without turning on the receiver, no audio device is installed. When I then turn on my receiver, it doesn't matter, no audio device is installed. Why not? Why does the receiver have to be on at all times to maintain its status as an installed audio output device? Turning off my receiver shouldn't necessarily terminate the relationship as an audio output device with the NUC, and it CERTAINLY should restore itself when I turn the receiver back on later. I should NOT have to reboot my NUC to get sound passed through to the receiver again. What if I turned off my computer speakers for 5 minutes. Imagine that I then turn the speakers back on and sound wouldn't play. Imagine if I had to reboot to get my speakers working again. Ridiculous right? That's what's happening here. I turn off the receiver, leave the NUC on, turn the receiver back on later, and NOPE, I have to reboot to get sound to play again. Isn't there a way to reinitialize the audio to recognize that yes, my receiver is actually turned back on and ready to receive pass-thru sound?
Is this clearly stated? The OP was fairly clear on the issue, and I have attempted to clarify further anyway since it doesn't appear that the question was answered. How will this issue be fixed?