Do you have any problems with other applications? When you save the file, how large is it? If this is Demo5, then it is likely a problem with dumming down the demo. If it is full Bryce5, then it might be a hardware problem. Are you running on Mac or PC. If running on Mac, allocate as much RAM as possible to Bryce in the OS. If running on PC, your RAM may be having problems with your motherboard. Make sure your largest chip is in the primary slot and that it isn't PC133 when it should be PC100 and vice versus. It could also be that you have set to branch and leaf ratios too high. Running out of suggestions quickly...