Solved
All worlds disappeared when a new Sim was added
I recently created a new sim through the new game option, using the story method to create. When I placed the sim in a world, I noticed all my other households were gone. It was only the new sim and ...
@LordEXO21 When you click "New scenario" at the Main Menu, you're creating a new save in which to play the scenario. If you want the scenario to take place in one of your existing saves, you need to load that save, then create a sim using the option you see when in the Manage Worlds screen.
I'm not sure what you mean when you say you'll lose a week's worth of progress. Do you mean that you've played the scenario for a week and don't want to lose that sim's progress, or something else? Saves can't be combined directly, but you could always save a sim or household to the library and place it into a different save. I don't know whether the scenario would still be active—I'm guessing not—so it would be best to play that out first.
