~Slightly modified to make the instructions pertain to Call of Warhammer
-The Holy Pilgrim
I can recommend following actions as steps that can directly influence your game's stability, they won't always work, but are worth trying:
0) Absolutely necessary - run the game as administrator or you'll experience fatal graphics errors, CTDs and other issues (particularly on Win7 and Vista).
Short How-to on fixing this:
1) delete all map.rwm files from data\world\maps\ - do that each time after updating mod files
2) delete strings.bin files from data\text\ folder - rarely necessary
3) disable file cache - fixes old savegames
4) disable the advisor - crucial to maintain battle stability
5) turn UAC (User Account Control) off if using Vista/Win 7 and proceed to step 6 - absolutely necessary to keep any stability
6) reinstall MTW/CoW
7) turn autosaving off - may help in getting rid of campaign map CTDs
Other means of keeping good stability:
8) reinstall graphics card drivers
9) don't use multiple submods without making sure they're compatible
Regards
Extended info on disabling UAC in Vista\Win 7:
a. Win 7 - Press Start, write "UAC" in search window, "Change User Account Control settings" should be found - click it.
Move the slider downwards to "never notify" position.
b. Vista - Try Win 7 method, but untick "Use User Account Control..."; alternatively you can go to main User Accounts page in Control Panel, click "Change Security Settings" and then untick beforementioned element.
c. Press "OK".
d. I recommend uninstalling CoW and making sure Call_of_Warhammer\data directory is deleted (you can keep saves, preferences etc).
e. Find compatibility folder and delete it, make sure you backup any savegames found there (there might be no saves inside as well):
C:\Users\YourUserName\AppData\Local\VirtualStore\Program Files\Sega\Medieval2 Total War (default path, could differ a bit)
f. Install CoW following usual routine.
g. For players confident that they installed correctly: skip uninstalling part and go straight from "c" to "e".