Re: SIM doesn't interact with other SIMS, only with objects?!

Are you using mods ? If so, remove them and delete your cache files.

Mods need to be updated with every patch or you will run into issues.

Go to documents\ea\thesims3 and delete these files

• CASPartCache.package
• compositorCache.package
• scriptCache.package
• simCompositorCache.package
• socialCache.package

^^ I found this and it worked, hope it helps