Hi everybody,
I also have the same problem with that missing items in few recent projects. From what I heard, it looks like because of the GROUP/ COMPONENT issues. The fact after having some annoying of missing material layers, IES lighting data, I tried the most common way using copy/paste to a new plain file. So when I hit render with a new file, it turn out with nothing but the background !! Then I select all and put into GROUP. Wow..Objects got back in render frame again but material layers and lighting data still missing. So strange..Somehow it'a last solace than nothing !!

Hello,
I'm Bojo, and it's great for me to join the community. I'm an architect and a sketch up user for years and still look forward to explore more about SU capacity. Really want to learn more from all the masters here , maybe nearest target is about making a simple animation (I like Lumenrt but I guess my PC can't afford for that frustrated render)
Good day guys!
Bj