Here's a problem that's been bothering me now and then since my iMac (High Sierra) was new: quite often I will get no sound from YouTube, nor from Spotify and iTunes sometimes refuses to plan at all. And clicking the speaker icon top right on my screen, a greyed out menu would tell me that the sound was turned off, and there was no way of clicking the option of turning it on. Still, JRiver WOULD play as normal.
Yesterday, I closed JRiver when this happened, and the other programs would work as normal. AND the options of the sound menu were no longer greyed out.
The output settings of my sound menu/sound card are set to Internal speakers (built in). In JRiver the Tools/Options/Audio are by default set to (Default) (Core Audio), but may be switched to Built-In Output (Core Audio). It will not help, though.
This is getting a bit tiresome, and any input for a final solution to this would be much welcome.
BTW, turning the computer off/on will help, but not for long. And it has been a problem with both version 23 and 24.