I just tried tastiger's attic conversion and also got normal results, the same as mickmca above. Had no shadowcam names with underscores and was able to delete lights right along with their shadowcams -- no problems with the file. You've "stumped the band" and may want to just unzip that sucker and start over again. (or, if youve done work on it, export the model from your current scene and import it into a clean one.) btw, you did get that the material "Rays" are supposed to be transparent light beams coming in through the windows? They weren't your mystery hot spots were they?