Thanks ,
yes somehow the savegames are corupted. After deleting them it works again. But after to many hours I refuse to start at zero. In a steam chat they talked about reinstalling steam to make it work, but its to late for me today to try that. If you have not found it here is the link:
https://steamcommunity.com/app/834910/discussions/0/4904953131465333725/
Hope it helps