The Sims 3 Store has just released a store content patch to correct incompatibility issues with some Store Content, and updated all store objects’ compatibility with Seasons. Thanks Rincon Del Simmer !
I had the same problem awhile ago. Bought a couple expansions on Amazon as they were on sale. I actually just go through Origin now. Download the Origin app and register your game on there. I actually like running through Origin over Steam anyway as you get some free downloads for registering the game, as well as some free Sim Points. For example, yes you can use mods. Unzip them and copy them into the Sims 3 Documents folder. (C:\Users\Username\Documents\Electronic Arts\The Sims 3\Mods\Packages) Not sure on being able to run the game via the launcher. However, the launcher can be used to install .Sims3Pack files if desired. Look for a file called -- Sims3LauncherW.exe. On this page you can find all free downloads from The Sims 3 Store. New! – Fashionable Fitness Set. – Year of the Horse. – Gifts for the Holidays. – No Tricks, Just Treats. – Happy Mardi Gras! – Sims Santas. – Toyota Prius family collection. Deleting these cache files help with troubleshooting issues with the game along with to clear the game's memory of the bad or removed mods/cc. --- Follow steps 3 - 5 till you're done installing and testing the Nraas Mods. Start a new folder for a new set of mods, for example, MTS. Install 5 or less files at a time.See More Details ›. 17 items are included in this set: (click on thumbnails for a quick view of the item) 1,900 SimPoints. Buy Now! Add to Cart. Add to Wishlist. Gift this Item. Please make sure you have the latest FREE game update to guarantee that this content is fully functional.
Store content can and will work with TS3 from Steam, as portrayed in the image of the store content being installed. Anyone who owns the Steam version of The Sims 3 may have encountered issues in the past with getting content from The Sims 3 Store to work with their game because the web browser cannot find the application associated to the2jXbM.