@Alpaca - I think I understand why we were hitting a problem with 2 (or more factions). Its the pope again. Doesn't seem to be an issue with the AI running as the disable papal elections is switched to off. However, for the normal single player it was still on and causing the crash as none of the actual factions was a papal faction.

In your new set of files you may want to include an amended SM factions with that attribute removed from the Papal_states and also remove it from the Strat file ( I did it to both to stop the error haven't tried if only one of them would stop it).