Re: Sims 3 won't launch says error if not online

@lizzielou6590  Just to clarify:  All of your packs work when you're connected to the internet, but none of them do if you're offline?  Try clearing Origin's cache, and if that doesn't work, uninstalling Origin "the hard way" and reinstalling.

https://help.ea.com/en-us/help/faq/clear-cache-to-fix-problems-with-your-games/
https://help.ea.com/en-us/help/origin/origin/manually-uninstalling-origin/

If these steps don't help, please post a screenshot of the error you're seeing.  You can take one by hitting Windows key-shift-S and dragging your cursor over the section of the screen you want to capture.  Then open Paint or another image editing app, and crtl-V to paste the screenshot.