edit collider crash

Hi,

I had this project, upgraded to 4.6.1, all ok... now for the first time I edited this prefab in my older project, saw the edit collider button and was fine, did the same again to another prefab and it crashes Unity...

to name a few, I received 999 errors in my console in about a second, really rips up Unity...

actually it's crashing my console,...

edit collider crash