mods

@kaylabear222019 I'm very sorry that this happened. Did you check inside your "The Sims 4" folder to confirm if your Mods are missing there? If they are no longer in your Mods folder, if you have a backup of your 'The Sims 4' folder or your Mods folder from your game you could get your Mods back from that. Or you can see if your mod creators have an updated (or properly functioning) version of your mods that you can re-add to your game.