I had been getting crashes while advancing from the first turn of the Grand Campaign. Unfortunately I didn't save the !Main text log file but I did take a look, and the critical error was caused by trying to access a .csv file in the My Games\Wars of Napoleon\NGC structure, reporting it was in use by another process.
I use a NAS (Synology) and cloud save all my documents directory using Cloud Station. When I removed the WON directory from my cloud station config, the crashes have dropped dramatically.
It may well be the case that AV software can cause similar issues/crashes. It may well be the case that slightly looser handling of file contention (wait & retry) would clear up crashes for some people.
Public beta 1.02