@kitkat93 The unknown error is a relic of the 32-bit version of Sims 3. Which one did you install, and how did you install your packs? And where do you see the unknown error: when pressing Play in Origin, or opening the Sims 3 launcher and pressing Play from there?
It would also be helpful to know the full specs of your Mac. Please list everything here, including operating system; be sure to leave out your serial number.
https://answers.ea.com/t5/Technical-Issues-Mac/READ-FIRST-Sims-3-Mac-Help-Guides-and-Troubleshooting/m-p/4756624#M2878
