It also sometimes happened to me. I guess it is a problem with RAM. For big games you sometimes have to clear RAM before calculating the turn. Close all other applications and programs. Always start CMRT new before playing a large battle. This is because CMRT uses more and more RAM every time a game is loaded. So if you play lets say 3 different PBEM consecutively the more memory will be reserved for CMRT. And this could lead to freezing the game. So possible solution. Best start your system new, fire up CMRT and nothing else. This shoudl give you enough free memory to calculate the turn...