I have never had problems with stopping time in my games (as long as I follow the precautions that I outlined above), and I have many games running on multiple computers for testing purposes - all set for Stop Time. If someone who is having this problem would care to keep track of exactly what you're doing (what steps you take to stop time, whether or not you click play after stopping time, when and how you change players, and the exact steps you take when you start the game(s) back up), perhaps we could identify what is causing the disasters in your games.