Multiplayer, can host with windows, can't with mac?

Zendog7

Trying to multiplayer with the gf.
She has Mac I have windows 7 laptop. All up to date etc.

Would rather she hosts the game so she can be protagonist, having never played before it'd be great for her to experience the story. I've played a million times and would rather just take a back seat and let her make the calls etc.

Problem is whenever characters are selected and we've both selected 'ready', when she is the host and clicks 'start game', her game crashes to desktop. On my comp it then tells me session has been terminated.

More frustratingly, if we do it the other way around with me as the host, the game runs sweet as a nut, but there is no way to have her as the protagonist without using each other's computers, which is a bit of a crap solution.

Would be better if the game just worked.

Any thoughts people? How a 15yr old game that's been 'reworked' doesn't work is really not good enough

Thanks in advance x

Zendog7

This is for bgee btw. No mods, both fresh installs, version 2.3.67.3 (I think, going from memory).