In reply to your post on the other thread
It hadn’t occurred to me to try importing instead of exporting. It is amazing how the problem file imports extremely quickly. Then changing to any other view than wireframe results in the very long delay experienced when trying to open the file normally, along with the high RAM and CPU use.
Just turning off (unchecking) the texture within the chair material seems to have solved the problem and that avoids needing to reset up the environment, sky etc.
One thing, I can’t figure out how to detach the texture completely? It seems like we could do with a 
icon to remove textures completely without having to choose an alternative.