When Enlighten locks up on 7|11...

Is there a way to tell what mesh is making it choke?

 

Make sure mesh is manifold i.e., its all four sides are closed

 

What do you mean by "all four sides are closed"? In game production there are a lot of cases where open meshes are required (mostly for optimization). Does Enlighten (or the way Unity implemented it) really force us to have closed meshes?

 

That's true, having few non manifold works but with lot of it kind of stucks......

Another solution read somewhere is is to add everything into One gameObject and then scale that game object to 0.01 > bake lightmaps at relatively higher resolutions > rescale back....may work not tried in depth...

Find more on discussion here,
http://forum.unity3d.com/threads/your-tips-on-speeding-up-lightmapping.376736/
http://issuetracker.unity3d.com/issues/stuck-at-clustering-jobs-when-baking-lightmaps
http://forum.unity3d.com/threads/po...k-at-5-11-clustering-or-7-11-lighting.309746/