Hi @ladynakia Unfortunately, a risk with a very experimental mod like Zerbu's Copy Worlds is always going to be that at some point a save become unrecoverable. The mod description includes a lot of warnings.
One time when I had a save go really bad but could still access it, I rebuilt as much of it as I was interested in and could rebuild in a new save. If you can access Manage Households, you can save households to your Library. That will retain their current relationships within the household, careers, skills, and the like. Any lot that you can enter in build/buy mode from the World Map you can also save to your Library. Then in a new save, you can add them back in. When I did this, I used the Club system from Get Together to quickly reintroduce Sims to each other. I used UI Cheats Extension to reset their relationship levels between households.