Just curious as to whether anyone else is experiencing this issue. When I export project files Site Designer sometimes crashes. It does not do it every time, maybe 20% of the time. I have to be very careful to save my project file prior to export. I contacted support and sent them some project files, but they say they are unable to duplicate the problem.

I'm a Windows user, so I cannot say much about your problem. However, there was a time, some years ago, when SD would crash for me if I tried to export before saving. This happened when Hans Top was the one calling the shots at CC, and he said that he had got this fixed so that there would always be a 'save' before export.
Maybe this was forgotten for Mac?