I have a similar problem.

SPOILERS AHEAD

I do the final battle, I watch the entire conversation with Lucian, and then it freezes. Alt+tabbing back to windows then causes the game to close down.

I've already seen the final movie that is supposed to follow (I checked the Divinity 2 Video/Story folder), but in game it refuses to load the movie.

Is this related to me using a language hacked version? I do not use a No CD crack and I do have the disk in the tray.

He's not just medieval, he's fully evil! The baboo will get you, https://www.nilteran.com