Black Square in Britchester

I was going to bring my sim to an event (study session) at the library in Britchester. The game froze on the loading screen, though it seemed like the event was going on in the background (I could hear the sounds and my mouse seemed to be able to click things.) I force quit, and afterwards, when I went to return to game, there was a black square randomly on the screen, but only when I went to Britchester. 

I repaired the game, deleted local thumb drive, and yet the black square was still there. I have mods and cc, and removed the folder but the issue is still there. It seems the library is broken. How can I fix this issue?