Purchased Sims 3 Worlds Not Showing Up in Game or InstalledWorlds Folder

griloabstrato​  Please see the first post of this master thread, specifically the "I can't install" section:

Sims 3 Store world can't register/install | EA Forums - 11143823

Thanks! That was really helpful — I found all the worlds in my Purchase History. That said... I’ve run into another issue now, and I’m hoping you might be able to help again, lol. I downloaded the files, but the Sims 3 Launcher won’t let me sign in. I’m using the correct password, but it keeps asking me to log in again and again, and because of that, it won’t install the content. Do you have any tips on how to fix this? Sorry to bother you...

griloabstrato​  You're not bothering me at all; this site is here for people with questions and anyone who enjoys answering them.

You don't need to login to the launcher or Main Menu to play Sims 3, and you shouldn't need to login to the launcher to download Store content.  What happens if you don't login?  Some players have reported that they keep being asked to login when downloading content, and sometimes this is an account issue, but others don't know they can just skip the login entirely.

If you are being asked to login when you download an item, try renaming the Sims 3 folder in Documents > Electronic Arts.  Doing so will keep the game from reading your saves and other user data, which can all be restored later; for now, just see whether it works.

If it doesn't help, please create a new admin account on your computer and try downloading some Store content there.  Don't link it to your Microsoft account or any email address (Windows), or to your Apple ID (macOS); you should be able to decline to do so in either case.

If this doesn't help either, please let me know whether your computer runs Windows or macOS.