Do you remember doing anything in particular that might have frozen the game? Any ideas of replication?
Only things I can think of that it never crashed in battle or while walking around town/tavern/village or in the menus so only on the map screen. I can't completely recall but I think I was always speeding up time when it crashed. But nothing else in particular. Once I was just standing still, waiting for a sieging army to move, another time I was chasing an army, once I was travelling from Ocs Hall to Charas and it crashed around the midpoint and once I was just standing next to a friendly city just to see if it would crash on the start of day 366 of the campaign. It did crash but right after as I tried to replicate it, I decided to change my display from fullscreen to windowed and it no longer crashed on the start of day 366. I changed it back to fullscreen afterwards and it crashed maybe an hour later. That's about all I can tell you, sorry.
EDIT: I'll try and see if it crashes on Windowed mode as well. If it does then we could at least rule out that it's not dependent on that at least, right? Also, it always asks if I want to launch the game in Safe Mode because it crashed in the previous session and I've tried it with launching in safe mode and not but both ways have resulted in a crash.
EDIT2: Sure enough, it crashed in Windowed mode too after about 15 minutes of standing still outside of Sargot at Fast Forward.