Found the problem!
Logic Pro crashed when playing a MIDI file and starting/stopping the playback
After stripping down the instrument part by part, I could isolate the problem.
I have a sampler that plays hammerback sound, that is, the sound of the piano hammers, falling back after releasing a key.
It turned out that the Release Trigger MIDI processor for that sampler had the Time Attenuate activated, for some obscure reason, or mistake... When I deactivated that, Logic worked as it should.
I also have regular release samples that has the Time Attenuator activated, as it should, but the the curve is reversed, sinve I wan't those samples to trigger at a lower volume the longer a key has been pressed prior to release.
If the thing that caused Logic to crash was the combination of these two release samples, or only the Hammerback, I don't know, but when I, or anyone else, have more time and want to do a test, it might be a good idea. This was the AU version, and only on Logic Pro
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