SWMBO's iMac will play streaming audio, and will play audio frorm an MP3 file. But when playing a video from YouTube or Facebook, the video plays with no audio.

I know even less about Macintosh computers than I do about Windows (no small achievement there!) and have no idea where to start looking to fix this. It is a recent problem, the computer used to work properly.

The problem persists whether playing through the USB headphones or through the build-in iMac speakers.

tanstaafl.