Sims 4 won't launch after Growing Together

@Sibilla2334  If you haven't already, please clear the EA App's cache:

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

and restart your computer.  Then repair the game: open your game library, click Sims 4, and select Manage > Repair.

Please let me know whether you can play at all after this, and if so, whether the Growing Together content shows up in-game.  Ignore the pack downloading message if you see it.

@Sibilla2334  Please try one of the suggestions in the first post of this thread, whichever one applies to you.

https://answers.ea.com/t5/Technical-Issues-PC/CURRENT-ISSUE-Sims-4-DLC-shows-as-installed-won-t-load-in-game/td-p/12416260

@Sibilla2334  Does the EA App currently think Growing Together is installed?  (You can check under Manage > Manage Add-ons.)  If so, please run the search described in that thread and post the results.  If not, please let me know if you see a Download button for the expansion and what happens when you click it.

@Sibilla2334  Please let the EA App (try to) download the pack, then run the search I mentioned.  I'd like to see whether the Growing Together data is actually downloading, and if so, where it lands.

@Sibilla2334  The packs are normally downloaded into [install path]\The Sims 4.  If you didn't change the default location in Origin or the EA App, the full file path would be one of these:

C:\Program Files (x86)\Origin Games\The Sims 4

C:\Program files\EA Games\The Sims 4

However, the entire point is that the pack isn't downloading into the correct location, so it doesn't make much sense to look there.  When you searched, did you click "This PC" first?  Not doing so could restrict the search to Quick Access or whatever is already open in File Explorer.  Additionally, there should be at least one EP13 folder even without Growing Together installed: the Delta folder that holds patch data should be present in any fully-updated game.  (This is true even for people who don't own the pack.)  So if you didn't at least find that, the search wasn't complete.