Ok.
1. Move the Electronics Arts folder found in Documents to the Desktop.
2. Start The Sims
3. Exit The Sims
4. A new Electronics Arts folder will have been created in Documents.
4. Move everything inside the old EA folder on the Desktop into the new Electronics Arts. If it asks Replace? Yes.
5. Start The Sims.
6. If The Sims still won't start? Move just the The Sims 4 folder to the Desktop.
7. Start the game.
8. Exit the game
9. A new The Sims 4 folder will have been created.
10. Open the old TS4 on the Desktop and move your saves, screenshots, Tray and the Options.ini file into to new The Sims 4 folder. If you have mods or videos move those, too. Replace? Yes.
You should now be good to go.
DO NOT trash anything until you a certain everything is working.
It maybe that all you need to do is a steps 6 thru 10. Moving the EA folder may not be necessary. But that's where I started.
Also. Always backup everything, before you do anything. MacOS comes with Time Machine. It's easy to set up. Easy to use. It's not perfect, but it's better than doing nothing.
