(Mac) Issues with launching Sims3 Paradise Island and other Sims3 games

@Dusktreasure  The issue is that all the newer versions of macOS, from El Capitan onward, will fail to authenticate Sims 3 discs.  The solution is to manually uninstall Island Paradise and then download it from your Origin library.  It shouldn't be necessary to do a clean uninstall of the entire game, but do make sure to remove IP's hidden library files before reinstalling it via Origin.  Here's how:

https://bluebellflora.com/manually-uninstalling-an-expansion-or-stuff-pack-in-the-sims-3-for-mac/

Your other packs don't run because the newest pack (by the date EA released it) is the one that runs your game to some extent.  So as long as IP is installed, Sims 3 will call for IP to be authenticated.

If you get an unknown error instead, please list the other packs you have installed, and I'll write out instructions for applying the usual workaround.