Farting sounds from midi file Mulab 7.4.8 – Page 3 – MUTOOLS Forum

One other thing I found, I think this has long been fixed though, is that in earlier version of MuLab, when it was left unattended for some time, not sure how long, it would distort the entire signal for some reason. The longer I left it the worse the distortion got. Although, I seem to remember it was only one MuX now I think about it. So it may have just been a faulty module or something.

But I doubt this has any bearing on your issue. Just thought I’d mention it as you’re using an older version, I can’t remember when this bug was fixed, think it was about two or three years ago, which may align with your version?