Try the
4GB Patch to increase the amount of virtual memory that the game (or any 32 bit application) can access in 64 bit versions of Windows. That usually helps if enabling Lockstep Mode doesn't (you can also try disabling 'Use Multicore').
A couple people have reported that setting the game to run in a window fixed the problem. To do so, edit the file below in a text editor and change the one to a zero in Fullscreen="1".
C:\Users\<UserName>\AppData\Local\Divinity 2\Profile\graphicoptions.xml
You may need to
set Windows Explorer to show hidden files and folders (covers Vista through Win 10).
