Hey there!
I have a project I’ve been working on for a while now, a few years off and on. Very early on it was passed between Unity ~4.3 on Mac and Windows a few times, and since then I’ve been developing on only Windows, upgraded the project to Unity 5, currently using 5.1, and it works perfect on Windows. But now that the game is pretty well complete, I was trying to transfer it back to Mac to make an iOS build of the game (I’m building to Android on Windows), but the Mac editor won’t load the project.