My wife has Windows 7 64 bit, and the newest mapsource, and usually she has no problems. We use her laptop with n-route for trips, and mapsource to see ahead, and just finished a 4500 mile trip. She only had 2 problems, when changing maps, once everything went blank, and one it panned to very far out, and wouldn't come closer. Both times she closed and restarted the program and it worked. She had been having problems before she downloaded the newest one tho.