@K_L_White10 Does putting the EA App in offline mode for a minute or two and then going back online help? It did for some players a few patches ago. This is different than playing offline, closing the App, and going back online later.
If you use a third-party antivirus, please disable it as well, temporarily, and then clear the App's cache again and try to repair Sims 4. As long as you don't do anything else at the same time, your computer should be safe.
Otherwise, normally I'd suggest uninstalling and reinstalling the game, but it's possible the EA App would throw an error when you tried to download Sims 4 again. So instead, if you have the room, it would be better to rename the program files, making the App think Sims 4 isn't installed. That way, if you can't reinstall, you can go back to your current install for now. This will only help if your computer has enough free storage though: 20 GB for the base game, more like 60 if you own all packs. You'll get the space back later.
In the EA App, open your game library, click Sims 4, and select Manage > View properties. You'll see the install location there. Close the EA App and kill the EABackgroundService in the Task Manager. Open the install location and rename the "The Sims 4" folder—you can just put one extra letter in the name if you want. The next time you open the App, it'll say the game isn't installed.
Restart your computer, and create a new folder where you'll install Sims 4. The folder should be on the root level of the drive of your choice, for example C:\Games is fine, but not C:\Program Files\Games. Try to install Sims 4 into that folder. If it works, great, delete the old Sims 4 folder you renamed to reclaim the storage. If it doesn't work, delete the new folder you created. If you use a third-party antivirus, disable it again, temporarily, while trying to install the game, and don't reenable it until you've launched Sims 4 at least once. If it helps, you can set exceptions for TS4_x64.exe and EADesktop.exe.
