@CORATHESIM You likely have two different issues here. One would be an outdated mod that's hiding the world. The other would be an outdated mod that's hiding the icons. Most of the mods that would do these things were re-updated for the For Rent EP in December, so I would suggest starting with these lists:
Staying on top of mod updates will help prevent these issues in the future. For packs that add new worlds, some mods will always need updating (or removing) before that world is accessible.
@ErykaNeko They have the items in Build/Buy and CAS, just not the icons. There's no need to check if it's downloaded. Game Repair is also not relevant here, and never something to test before testing mods.
