when I export to MP3, suddenly no sound!

I am running Audacity 2.0.5 on a MacBook running latest version of Yosemite. I think I got the zip version, but not certain…

I’m new to Audacity, but was doing pretty well after some initial problems. I need to export tracks in MP3, and was doing so with no problem, then suddenly there was no sound when I played them back. I don’t think I changed any settings. Any idea what might have happened?

The quick version of this is Audacity does not yet support Yosemite. Many odd things have been reported go wrong with this combination. I’ve been avoiding the upgrade until this is resolved.

As Koz says, Audacity does not yet officially support Yosemite.

If you mean that there was no sound in Audacity, try Transport > Rescan Audio Devices in the Audacity menu bar and reselect the device you are trying to play to.