I have had this happen as part of a larger (for me) issue. The person who does the voice over (actually under) for my courses has changed his hardware and software. When I tried to use his MP3 files (which have always worked fine) Lectora crashes when I click “Sync Events”.
As a plan B I had him send me the wav files. When I try to convert them I get what you describe and in the Audio editor the file shows as empty, and then it freezes (Lectora doesn’t crash though) – but I can’t use the file.
Plan “C” was to convert the wav files to MP3 on my end. I did so using Audacity, and these new MP3s also cause a crash.
M4a files behave the same as the wav files. Convert to a 0 byte file which crashes the editor.