Can you explain what your are doing when you edit midi files and I will do the same as you and see if I get the same problem.

Are you in USA or Europe

Hallo Tony
I open the GM side and there you have all the tracks and you can change sound, effect, pan. and also you can assign a track to the vocalizer. This is what I try to do and after this changes i push the save button, and sometimes it works and sometimes it freeze or the tempo will change
Player 1 (Hasse) I live in Sweden