Sorry to have been vague. This happened when I was saving to HD. It also happened when I THOUGHT I had the size of the file(300MB) plus 200MB of space left but I could easily have been wrong. (I wouldn't call this "plenty of space") One of the problems is that if you run C4 in non windowed mode you will never see Windows warning that drive space is getting low. I run on a notebook and HD space is always tight! :-) Thanks for the confirmation. At least its not my hardware.