Musescore 2.0. sound does not work???

I have the latest musescore, and the sound does not work on playback or when adding notes. I've tried deleting and re-downloading musescore twice, and neither time did it work. It all started after i muted my laptop so i could make a peice without hearing the notes. However, it's kind of annoying when you have to upload the peice just to hear the assignment your working on.
I'm on a MacBook Air, by the way.
Does anyone know how to fix this?? I know that these posts have been made before but