My question for you would be how much editing did you do and have you saved, closed RB and restarted it. Every "do and undo" you make during creation and editing makes tmp files. Eventually the program runs out of juice and starts crashing. That happened to me MANY times and now after a hour working on a song I will save, close RB, do %temp% and clear temp files in windows, restart RB and reload the song at the latest save point.