@wdrlj79w7wnj
Yeah, you're probably right that it's either a CC item or a mod causing the problem if it's just one lot. So, you'll have to figure what is causing the problem and remove it. First thing you do is make a backup copy of your save. That way, if something goes wrong, you have the backup to fall back on and try again.
The easiest way is if you can get to the lot in build from the map. If you can, save the lot to your Library. Then close the game and move your mod folder to desktop or somewhere else out of the game path. Start the game and create a new game. Once you get through making and placing the sim, go back to the world and go to the lot that you want your apartment to be on. Install the lot you saved in your Library. That will clean out all the CC. Then save it again to your Library. The close the game, move your mods folder back in and start the save where you have the problem. Go to the world and move the household out if you haven't already done so via Manage Households. The go into the lot in build from the map and replace it with the CC free on you just saved to your Library. Exit build mode and place the household again. Try to enter the lot. If it works, you'll probably get the items missing and replaced popup but that's ok. You'll need to replace the missing items either going to build from live mode or from the map. Your choice.
Now the 2nd issue is figuring out what broken CC caused the issue. One way I use is to look at every CC item, CAS and build, in Sims4Studio (S4S). If you have a lot, it will be time consuming, but the effort is worth it, imo. You'll probably find a bunch of broken stuff like I did including things in your mods folder that you downloaded but never showed up in the game. You can usually tell a broken item by the way it displays - a lot of broken items won't display at all, and others will look wrong. But you might not find everything as some items look perfectly fine but don't work in game anyway. It will help you find the majority of the broken stuff though.
While you're at it, you also might want to think about each item and get rid of all the stuff you have that you don't use. Eliminating the broken files and reducing the amount of CC you have will help game load times and performance.
Hope this helps.
