FO3 runs pretty well on my Win 10, except for a single (gamebreaking) issue: the savegames won't load. If i try to load a savegame AFTER quitting the game, it will freeze on the loading screen, unable to proceed and making me force quit every single time. But if i try to load a game during the same gameplay, it will run smoothly. Does anybody have an idea on how to solve this issue?

New Vegas does this to me as well, but I end up having to start a new game, then loading it works fine afterwards. It's not all the time. Supposedly using the CASM mod fixes it, but I've gotten used to manually saving into a new slot every 20 minutes or so that I didn't bother with CASM.