Comment 2 for bug 1800606

I assume that this bug was triggered by a teack. By luck, you have still the mixxx.log file from the crashing run.
It is stores as mixxx.log.x where x is the number of restarts since then.
https://www.mixxx.org/wiki/doku.php/finding_the_mixxx.log_file
This should contain the effected file as last entry.