Where is the Sims save file located?

[RincewindTheWiz]

Probably in "C:\Program Files\Maxis\The Sims\UserData". There's also a few other UserData directories, like UserData2, UserData3... UserData8. I don't know if these are used but it's best to backup these too to be sure. My best guess is that each UserData directory stands for one neighborhood, with UserData being the first one.