AllysonMaddison Windows Defender shouldn't be an issue, nor should the install location. But I would suggest doing a clean uninstall of the game with Revo Uninstaller (the free version is fine) and reinstalling to a different location, specifically a new folder created for only this purpose. 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. More details are in the accepted solution of this thread:
[CURRENT ISSUE] Sims 4 DLC shows as installed, won't load in-game | EA Forums - 11831673
Anchors don't work on this site at the moment, so use ctrl-F to search for revo and jump there.
If that doesn't help, please provide a dxdiag. Click Windows key-R, enter dxdiag in the run box, wait for the scan to finish, click "Save all information," and save the file to your desktop. From there, you can attach it to a reply using the paper clip (Attachment) icon included with the other formatting buttons.