Unity is crashing on loading of certain Maya files.

I've recently run into a problem where on the loadup of Unity, it will hang up on a .ma file and crash. It's a different one each time, and I don't recall changing anything about the way I save Maya files. What could be causing this?

Make sure that the version of Maya is consistent. The FBX Exporter/Importer hangs when the Maya versions are different.

I had problems similar to this when an artist was working in Maya 2009 and I was running Maya 2011. The Maya ASCII file could not find the correct FBX plug-in and therefore hung/crashed.

You should also make sure your FBX Utility plug-ins match.