Unknown error occurred message when launching game! Help!

[kylalouise9]

So I bought Sims 3 and the expansion packs: Late Night, Pets, Master Suite, Outdoor Living, Fast Lane, and High-End Loft stuff. I downloaded all these on to my 2011 MacBook Air that was running El Capitan at the time, the game ran smoothly as it should. When I updated to High Sierra it still worked fine until I started downloading custom content. This is when I began to receive the unknown error message. I have tried clearing everything related to sims off my mac and purging but it still doesn't want to work.

[Bluebellflora · Accepted solution]

@kylalouise9

Ok. So you need to install just the base game, patch it then download Late Night. Follow the instructions in this thread to get the game files properly installed, including the instructions on getting the EP to show up in the Launcher (Late Night will most probably not be in your Applications > The Sims 3 folder either). When you can successfully launch the game then install each pack, repeating the steps and checking to see if your game works after each install.

[Bluebellflora]

@kylalouise9

Did you get rid of all the hidden residual files or just use the uninstaller?

[kylalouise9]

I got rid of all of the residue files. Everything totally cleared. I followed your instructions on how to do that. Ive done this twice

[Bluebellflora · Accepted solution]

@kylalouise9

Ok. So you need to install just the base game, patch it then download Late Night. Follow the instructions in this thread to get the game files properly installed, including the instructions on getting the EP to show up in the Launcher (Late Night will most probably not be in your Applications > The Sims 3 folder either). When you can successfully launch the game then install each pack, repeating the steps and checking to see if your game works after each install.