bizarre cause of lag/freeze issue - 1st post updated 8/26/13

I still don't know much about building and particularly next to nothing about roofs, but I was recently surprised when Auto Roof seemed to turn on by itself and put a regular roof on top of my Green House roof and flat roof tiles. It took me a while to work out what was going on. I think that game was corrupted though as the roof thing kept happening so I saved the family to the library and started a fresh game with them.

I haven't noticed any problems since.