Suddenly mp3 export files no longer play back or are garbled (but .wav exports still work fine)

I've been using Musescore for years and I believe I have the newest software. I've always been able to export all my scores as either an .mp3 or a .wav with no issues. Suddenly this summer, when I export an .mp3 the file either does not play back, or it plays back garbled. All .wav exports of the same scores play back fine. This happens on every score I've tried, both old & new creations. I've never had this problem before.

I've tried saving the sound fonts to the score, I've tried different playback software programs. I've tried reverting to factory settings. I believe I tried re-downloading the Musescore software this summer. Nothing has worked.