Doesn't recognize headphones as a playback sound option
Plug in headphones
Set as default output on the PC
Test: Make sure youtube plays through headphones
set preference for headphones as output device
listen to the music come through the speakers in spite of default setting
apologize to wife who is trying to read
Sound output interface seems to be a continuing problem for current versions of Musescore. I can't keep reverting to factory settings every time I work on a score.