I have been getting an Error after editing sketch lines in a revolved cut/boss for some time. "Sketch is open or intersecting" - while receiving no indication of where this sketch error IS.  -  I solved it by: Deleting the Revolve Feature in the design tree, then re-applying the Revolve cut or boss (selecting the axis from which to revolve).  VIOLA that cured it - rather than looking for non-existent openings/intersections in my sketch lines.