I got files that tell me when I save them something like "4 NoteEvent's duration is below zero. Are you sure to delete these NoteEvent?" I never delete those because I think I have checked every event in the file and I cannot find them. I only want to know how I can find those to see if I can fix them or delete them myself. I like this program a lot. I will understand if you don't have the time for this question. I did some programming in my younger years and I know how time consumming is the process.