No output from playback

Hello.

Recently, I've been composing some film music in MuseScore 2.0.0 on my MacBook Pro (OS X 10.9.5). I editted my score, played it, closed it, opened it again the next day and continued. It worked just fine.
  However, just a few days ago I managed to open my score and hit the play button - but it suddenly would not play my score! I turned on the metronome to hear if that would play: It was now the only thing MuseScore would allow me to hear. I even updated the software to 2.0.1; which didn't work either…
  Then I checked my  Preferences > I/O,  and the PortAudio was selected. API: Core Audio, Device: Built-in Output.

Is anyone familiar with this particular issue - or happen to have found a solution?

Thanks in advance
Mattimand