Any way to convert Mac copy to run on windows?

[Your Computer]

Maps, entities, static objects, scripts, materials, etc, are themselves cross-platform because the game itself is available on multiple platforms. So long as you have the game installed on each platform, your custom story will work the same when transferring your story to its proper location on another platform.

If you are trying to transfer the game itself over to a new platform, that won't work. You'll need to download and install the game for the desired platform.