Try the following
- Close the game
- Rename Documents\Electronic Arts\The Sims 4 to Documents\Electronic Arts\The Sims 4_Old
- Repair the game
- Start the game. All your content will be gone now as the game created a new folder. All your saves/.. is still in the old folder so not to worry.
- Start a new save game
- Check if you still have the error
- Report back with your results for further steps on how to get your stuff back.
Use this thread for the inventory issue: Items disappearing from inventory | EA Forums - 12597453
