Campaign progress lost after Restart

I don’t really know when it started, but atm when I finished a game in a campaign and I restart the game, the new progress is lost. I reinstalled the game, I checked for errors in game properties and found on google some topics with quite the same name in this forum. But those topics were just empty and closed. Hope someone could help me, because this is pretty annoying and so I am just not able to get through some campaigns.
Thank you!