I had an Error 12 just once in 8 years time and never when I played vanilla so I can hardly imagine that has something to do with it? It indeed rather is space related. I have two drives now (C and D) and made the mistake to install the game on the smallest one, so now I do have this issue occasionally. In fact I noticed the driver is in the red yet again a few days ago, which will mean saving probably will be a problem when I won’t do anything about it. I’d reinstall if it weren’t for 1.69...