No, I don’t (and didn’t) have any problems with saving/loading.
But I found out:
Seems a mod caused that loading error.
It looked as if a mod was just trying to update itselfs via steam while I tried to load the game. Anyhow this mod-update didn’t work, but it kept trying.
As I manually cancelled this mod-update (steam) and deactivated the mod (aceo), now the game loaded again, as normal.
My machine is running very well, even if it could be more powerful,