@YTekgurler Asking in this thread is fine.
There are plenty of approaches to installing Sims 3, all of which involve copying folders around, unless you don't have any of the packs that don't install correctly (Ambitions, Late Night, Fast Lane, and Outdoor Living). But by the time you're done, all you need is a folder for each earlier pack in the folder for your newest pack by release date. And for all but those four packs, the folder is actually an alias, taking no space on its own but pointing back to the original folder that you might have been told to copy.
So if you happened to have every pack, the only pack that would need to have other packs' folders is Into the Future. Inside ITF's folder, as in:
Applications/The Sims 3/Contents/Resources/AddOns/The Sims 3 Into the Future/Contents/Resources/transgaming/c_drive/Program Files/Electronic Arts
what you would need is a copy of the actual folder (2.something GB each for Ambitions and Late Night, 200 MB or so each for Fast Lane and Outdoor Living), and an alias for each of the others. The alias for each pack would be created automatically the first time you launch the game with Into the Future installed, so you wouldn't need to copy any files.
The original poster in this thread found that World Adventures was being difficult and needed to copy it outright too, not just let the alias be created. But that's not typical. Still, if you did get the unknown error when trying to launch (in this example) Into the Future, you could look inside the Electronic Arts folder in the file path above and copy over any folder that wasn't there already.
For all your earlier packs, as in, not the newest one by hte date EA released it, you wouldn't need to have folders for any other pack inside. So for example, in the Ambitions version of the file path above, all you'd see is the folder for Ambitions, not the ones for your earlier or later packs. You could in fact to into the folders for all the other packs and delete everything you find there, aside from the one folder that corresponds to the pack itself, i.e. delete the World Adventures folder inside the Ambitions folder but don't delete the Ambitions folder.
If you don't want to sort through this, then yes, you can uninstall and reinstall, and preserve your save. Your user content is in the Sims 3 folder in Documents\Electronic Arts, and it contains everything you create or download into the game. You can move this folder elsewhere while uninstalling and put it back when you've reinstalled and made sure the game is working.
Still, in your position, I'd try deleting the excess folders first. It seems like a lot less trouble, and if you test each time you clean out a particular folder, you'll know right away if there's a problem. Then you can open the trash and restore whatever you just deleted. If the game does work, empty the trash and move onto the next folder.
