Lots disappear when I travel to them

Pretty much as my title says, every time I travel to a new lot, the entire lot looks as though it has been bulldozed. I don't use mods, so there isn't that issue. I've just been downloading a lot from the gallery, but I don't like doing that for obvious reasons, aka the game should work lol. I also don't like doing this because then I end up downloading a lot that I don't have all the packs used on it.