Your computer will see the 64-bit version as a new application, so you need to install the new version instead of updating your game.
To get the new version, you’ll need to do the following. We suggest players on The Sims 3 version 1.67 or earlier update to version 1.69 which is available if you have registered your game and packs on your account. The Sims 3 for Windows PC works on both 32-bit and 64-bit versions of Windows. It’s not a remaster or remake of The Sims 3, but you’ll have to download and install it. You’ll want to use this version if your Mac no longer supports 32-bit applications. This new version is a compatibility release that lets you play The Sims 3 64-bit on Mac, use Apple’s Metal graphics API, and makes the application a fully native macOS app. Figure out if you need to switch to The Sims 3 64-bit on Mac and how to install the new version.
