Mac build will not start

I'm attempting to make a Mac build of a game I'm working on. Another developer has successfully built and run the game on his computer (with Unity Pro, I might add) but whatever happens, I cannot run the game - whether I build it or not. The application icon bounces, then stops bouncing after two or three tries. Then the OS tells me the application quit unexpectedly and asks if I want to send a report to Apple.

Nobody else on the team can replicate this. The game also runs fine in the Editor.

I know this has been brought up before on the Unity networks, but it's always been due to zipping or building on windows, and neither of those cases apply here.

How can I fix this?