I can pretty much duplicate this religously. I go all the way through 3 patrols and get back to port. End patrol, pass out promotions, medals, update or refit the sub and get my new mission. I get asked in port or out of port. Regardless of what I choose, the mission starts to load and then BLAM! Crash to Desktop. If I try to restart the mission, same result. If I go back to a previous mission, same result. It's as if EVERY saved game file suddenly and spontaneously decides to get corrupt. I have already gone to the point of uninstalling and reinstalling. I even updated my video drivers thinking that might be the source of my problems. I am not having any other problems with the game apart from some lag on the higher TC settings but that's just a livable pain. The CTD after my 3rd patrol is a game ender.