This is happening to me too & I've no idea what to do..
Have you tried the suggested tips in the thread?
Updating graphics drivers, turning off Origin In-game, a reset of the Sims 4 folder.
How to find graphics drivers:
Finding devices and updating drivers on your PC
https://help.ea.com/en-us/help/pc/finding-devices-and-updating-drivers/
Turn off Origin In-Game:
Open Origin, Select Origin > Application Settings > Origin In Game tab and click the on/off switch to disable Origin In Game. - This deactivates Origin In-Game, as it has been known to cause problems with games.
Restart the computer, to help the computer refresh itself, and try the the game again.
If that doesn't work, try resetting Sims 4 - see the lin below for details:
https://answers.ea.com/t5/Technical-Issues-PC/Sims-4-not-working-since-update-June-2018-update/m-p/6877112#M115472
Community Manager
