@jimbbq It's a known issue. Here's what an EA person had to say about it:
https://answers.ea.com/t5/Technical-Issues-Mac/the-sims-3-64-bit-amp-metal-release/m-p/9652952#M8808
You can post here if you want, although there's not much to be done:
https://answers.ea.com/t5/Technical-Issues-Mac/64-bit-Sims-3-content-not-in-Origin-library/m-p/9653314#M8830
@Hels Try running the Origin reset tool for macOS:
https://help.ea.com/en-us/help/origin/origin/how-to-reset-origin-on-mac/
If that doesn't help, uninstall the game (open your Origin game library, right-click, or hold down crtl and click, on the Sims 3 icon, and select Uninstall), reset Origin, and restart your computer. Download the base game only, and see if it launches. You'll probably get an error at the Main Menu, but that's a whole other issue, the same one from earlier in the thread.
If the game loads at least to the Main Menu, download one pack and install it, then see whether the error shows up again. Let me know either way. If not, you can keep adding packs.
