Ctrl_Morgan222 Please do a clean uninstall of Sims 3 and the EA App with Revo Uninstaller. Here's how:
[Read First] Running Sims 3 in Windows | EA Forums - 8323446
The idea is that you might have broken registry entries or something else wrong with the game's hidden files, data that doesn't get removed during the normal uninstall process.
LonaBoom The only reason OneDrive would have anything to do with what DLC is loading is if the game were installed into a OneDrive folder. And in that case, it's much more likely that the game wouldn't open at all than that somehow all the base game files would be intact but the DLC data would disappear. I'm not saying OneDrive isn't a problem, only that it's almost exclusively a problem for user data.