wav sound files no longer playing in FCPX (or iTunes) after Mohave update

I've been editing a podcast in FCPX with a bunch of .wav files. Everything was working fine until I updated to Mohave. Now even though the waveforms are visually apparent, the files no longer play in FCP. They also won't play outside of FCPX in iTunes. They will play if I hit command i and get info on the clip.

Help! I've made hundreds of tiny cuts. Can't bear to convert the wav files to another format and start again.