Step 1: Move the Mods folder to the desktop, Delete Game Cache Files and delete the localthumbcache.package file from The Sims 4 folder, in the Documents folder. EA/Maxis aren't responsible for broken mods/cc. If the game works when the Mods folder is removed, then one or more of the mods and/or custom content has become outdated and will need to be removed or replaced. *Note:* Custom content can become outdated with most new game patches. (Thank you Play for sharing these tips!!) Here are some steps to take if you've got mods and/or custom content in your game and are having problems with your game.
Steps to Take to Fix Issues with Mods/CC: Custom Content or Mods Don't Show Up In-Game
Steps to Take to Fix Issues with Mods/CC