Cannot start project after 4.11 Upgrade: Assertion failed - Editor crash

Update:
Crash was caused by a blueprint. Used VS2015 to debug the editor and a Breakpoint was triggered in the SkeletalMeshComponent c++ file where it iterates through the BoneIndex. After deleting the Blueprint i was able to start the project again.

I just upgraded to 4.11 and i can no longer start our project. (Previously 4.10.3)
When launching the project the editor crashs with the error message :

Assertion failed: (Index >= 0) & (Index < ArrayNum) [File:E:\UnrealEngine\UnrealEngine-4.11.0\Engine\Source\Runtime\Core\Public\Containers\Array.h] [Line: 785]
Array index out of bounds: 5 from an array of size 0

Full Log at : http://pastebin.com/EvT3Dn8T