I know this is an old thread, but was wondering if there is any new info on this issue? My system is pretty new, and I have this freeze problem all the time, especially when going from standard to guest/zoo keeper view or camera mode. I have tried adjusting the graphics speeds, etc. as recommended by the official site, and nothing works. If my system meets all the requirements (which it more than does), then this shouldn't be a problem, but it almost always is. It has gotten to the point that I have loaded the original game into the new system, and am playing it more that the new one, even though I just got expansions for the ZT2. Anyone have any ideas?