@zcc813 If you open your Origin game library, you should see two Sims 3 icons, one that says 64-bit and one that does not:
If you don't see the 64-bit version, you'll need to contact EA customer support and request that the "entitlement," as it's called, be added to. your account.
https://help.ea.com/en/contact-us/
If you do see the 64-bit version, you can simply download it, but you'll want to uninstall the 32-bit version first if it's still there. (If you have a Play button for 32-bit, it's installed; if you see Download or it's grayed out, it's not installed.) The uninstaller that comes with the game doesn't always work; here's a guide to doing a manual uninstall:
https://bluebellflora.com/how-to-do-a-clean-uninstall-and-reinstall-on-a-mac/
Some contents. of the Sims 3 user folder in Documents > Electronic Arts, for example saves, can be used by the 64-bit version of the game as well. However, you'll need to reinstall any store content you have and delete Version.tag. It's probably easier to move the entire Sims 3 folder to your desktop, let the 64-bit version create a new folder, and then manually copy over your saves and anything else you want to keep.
