I haven't really got proof of this, but I think save games make the game unstable.
I can play for hours without a problem, but when I start saving (cause I have to quit, or just in case etc.) the game tends to hang without reason. Just instant freeze without a warning or messages in the logs.
The funny problem is I can't get the game to crash when running the debug version. It runs terribly slow, but even saving ten times in fifteen minutes doesn't make it hang.
I have a save game added from Sleepiburgh which I want to use, cause I took a creature from the previous map, but after five to ten minutes of play it hangs. Not at a specific moment as far as I know. The log file says nothing after the crash.
The game doesn't crash back to the desktop it just freezes. I have to use the taskmanager to kill it.
The save game is not from an older version btw.