re:Rendering View, (greyed out?)
the "RenderView" is Greyed out, or at least you can not
see or access it any viewports..
This happened to me: Nothing you (I) could do about it.
and tried to find what is wrong... that was a waste of Time.
1) Open the scene,
2) Select everything,
3) and export it all out of that "Maya/ folder".
4) then import into a new projects folder