I just tried dulicated the household that wasn't opening to see if it was just that one, and now the second household isn't opening either.
It's just a game reset. Did you even look at the link ?
Anyways, if you're on a Mac, I can't really help you. I'll see that gaa, our mac specialist can help you out.
-Duplicating the household would only check if it's a problem with the world you're playing in, which it seems not to be. You need to see it if that specific family or any of your other user data by doing a factory reset. It's only temporary if you follow the instructions correctly, and you'll be able to put everything back if it's still happening.
To do a factory reset on a Mac, there are some instructions in this link under "Primary Things to Do First": http://answers.ea.com/t5/The-Sims-3/Links-to-Mac-help-threads-and-guides/m-p/749664
-Also, you should check what patch your base game is. Go to your Sims folder under Documents and open up the text file "Version.tag." (You can open this file with the application "TextEdit" if it asks you to choose one.) What number does it list? If it doesn't start with 1.50..You need to try patching manually. Here is a post where you can find the link to the SuperPatch for Macs: http://forum.thesims3.com/jforum/posts/list/549552.page
Does the game now work after being patched?
Let me know how doing those things turn out. Hopefully it'll solve your issue.
