Using 1.6.2 and 1.6.3 on a mac. Never had issue before. 

I thought it was due to use of antialiasing (as every time I tried to add support with antialiasing on, the program would get about 75% of the way done with the supports and then crash).

Tried without anti aliasing and did OK on some models. I would click aa back on after adding the supports. 

Tried again today with a few models on the bed (without anti aliasing). Small models had no problem. Large model crashed 75% of the way through when clicking PLATFORM button in supports. Very frustrating. Any help?