I can only do ESC+Save game (by now it seems to work) or the mission given/completed autosavings.
I dont use quicksaves/loads for fear of frustrating CTD.
All my automatic saves when changing levels are corrupted (even the very first one): when I go to the "Load game" option, the save appears normal but the thumbnail screenshot appears like those an detuned TV-screen (those black-grey-white blizzard like screen).
any ideas how to solve it?
EDIT: quick loads/saves also work.