Transfer save files from Mac to PC

Hey all. I have been trying to load saves started on my Mac on my PC via dropbox, email, &c to no avail. Every time I try to load the game on PC, the game crashes.

Yes, I put the file in the correct spot, yes I have tried multiples times with different saves.

I read that it is possible to do but I'm not sure what I'm doing wrong.

Anybody out there who can help?

Thanks