10. Can I transfer saved games between Mac and Windows versions of Civ5?
This is not supported by the Steam Cloud system for transferring saves. However, you can do it manually, by copying the save file via USB stick, Dropbox, email, shared drive etc. Find the Saves folder, where the files are stored, as follows:
On the Mac:
Steam: ~/Documents/Aspyr/Sid Meier's Civilization 5/Saves/single/
AppStore: ~/Library/Containers/com.aspyr.civ5campaign/Data/Library/Application Support/Civilization V Campaign Edition/Saves/single/
On Windows XP (other versions of Windows may vary):
My Documents\My Games\Sid Meier's Civilization 5\Saves\single\
Note that Civ5 updates have frequently changed the file format, so you can only be sure of opening a Windows save if your Mac Civ5 is at the same version as the Windows one.