Re: Sims 3 on macOS High Sierra
@erinalexxx Since you've uninstalled and reinstalled multiple times, it's best to do a clean uninstall before proceeding. The uninstaller that comes with TS3 will miss some files which can interfere with later attempts to run the game. Once you've uninstalled, please reinstall the base game only and then run the Super Patch (digital download version).
https://bluebellflora.com/how-to-do-a-clean-uninstall-and-reinstall-on-a-mac/
The cause of your unknown error message is almost certainly that the game doesn't recognize your graphics card. This can usually be remedied, though, with edits to the game's .sgr files. If this is not something you're comfortable doing, just post your laptop's specs here, along with the device Id of the card, and Bluebellflora will help you get it recognized. Here's how to provide the relevant information:
https://bluebellflora.com/2018/07/24/sims-3-mac-players-i-need-your-help/#Information
Going forward, there's a very helpful guide to installing TS3 in mac OS. (Editing the .sgr files is step 2.) Depending on which packs you want to install, you may be able to skip some of the steps. Of course, none of that matters until you can run the base game, but here it is anyway.