How can I get rid of this black screen?

I have this black square randomly appear on builds I make. It can be fine. I save and go to the world screen, and suddenly, this black square appears, blocking a section of the build. When I then go into the lot, I can build and play normally, except when I turn to the area where the black square is on the world screen, the screen freezes, and sometimes my computer stops responding. It is not visible itself when you play in the lot, but it has the aforementioned effects. It does not go away when I fix the game or close the game, and it is not being caused by Mods or CC, as I do not have any. It also can be seen in the personal galley, so you cannot save the lot and get rid of it by bulldozing the lot and putting the saved gallery version down. It does not affect saving rooms, but it is not always possible to save, and it is tedious to reconstruct builds using individual saved rooms. I can get rid of it by bulldozing the lot but lose the build.