Does anyone know how to fix dead tracks in Garageband?

I recorded a song in Garageband with six audio tracks and one midi track. All of the sudden the playback stopped working. I can see each individual track volume moving to indicate that the song is playing but I have no sound. I've tried unplugging and resetting my interface, I've deleted and reinstalled GarageBand, no tracks are soloed or muted.... I have no idea what happened, but I'd had to lose all the work I put into this. Please let me know if you have any suggestions. Thanks!