There is possibly something wrong with the ground clutter shaders. On my editor I get "Material didn’t allow automatic setting of usage flag bUsedWithGroundClutter needed to render on this component, using default material instead"and then the editor just freezes and does not load the level. Other levels work though. Presumably I’m using a static that isn’t a clutter object for clutter, hince the message. Unfortunently I can’t fix this at present because the clutter is in my main persistent level. If it’s a related issue you are having you could try deleting your clutter layers if you can access them. WildCard has been informed of this bug so hopefully it will get fixed in the next dev kit patch.