Not Starting Up

NikaaRenaee​ Give these steps a try to clear this error up:

Power cycle your console:

• Turn off your console by pressing the Xbox button on the front of the console for about 10 seconds, until it shuts down completely.
• Unplug the console's power cable. Wait 10 seconds.
• Important Be sure to wait at least 10 seconds. This step resets the power supply.
• Plug the console power cable back in.
• Press the Xbox button on your console to turn it on. 
  
  

Check that your game is fully updated:

To set your console to automatically receive updates:

• Press the Xbox button to open the guide.
• Select System > Settings > System > Updates & downloads.
• Select Keep my console up to date for console and Keep my games & apps up to date for games and apps.
  
  

Check that your console system software is updated:

• Make sure your console is connected to the internet, and then press the Xbox button to open the guide.
• Select System > Settings > System > Updates & downloads.
• Under Updates, you’ll see:
  • Console update available. Select this button to begin your update, or
  • No console update available. This means your console is up to date
    
    

Delete your Sims 4 save files (Note! Please save your households/lots to your online Gallery before doing this step or you will permanently lose your families/builds)

• On Home, select My games & apps.
• Highlight the game, press the Menu button on your controller, and then select Manage game & add-ons.
• In the menu on the left side of the screen, scroll down to Saved data, then highlight the saved data for your gamertag on the right and press the A button on your controller.
• You'll be prompted to confirm deletion of this game save data:
  
  • Delete everywhere removes your saved data from this console, the cloud, and all other consoles you play on. You do not want to sync the Autosave from the cloud, you want the game to make a new one.
    
    

Uninstall and Reinstall the game:

Uninstall

• Press the Xbox button to open the guide, then select My games & apps > See all > Games.
• Highlight the game you want to uninstall, press the Menu button select Uninstall, and then follow the prompts.
  
  

Reinstall

• You can then reinstall the game by inserting the disc or downloading it again from the Microsoft Store or Xbox Game Pass, or go to My games & apps > Full library.
• DLC - Highlight the Sims 4 on the dashboard. Press the Menu button, Select Manage Games and Addons. Install all the DLC from there.