Re: Adding walls removes objects

@Libbiexox Do you have any Mods or CC? If so, please move your Mods folder from your "The Sims 4" folder [Documents > Electronic Arts > The Sims 4] to your desktop (save it for reference) and delete the localthumbcache.package file in your “The Sims 4” folder. Then check in a new game save to see if this issue is still occurring. If the issue is gone, please re-add the Mods/CC one at a time until you find the one causing the issue. If you have a lot of Mods/CC you can try the 50/50 Method.

Edit: Dose this post seem like your issue? https://answers.ea.com/t5/General-Discussion-Feedback/Building-walls-raises-platforms/td-p/9887168 I would be happy to test your lot in my game if you want to upload it. Also, if you could perhaps include a screenshot(s) of the issue that would be super helpful. Does this happen only on one lot or on all lots? If you save this lot to the library and begin a new game save and add this lot is the issue there then?