Multiple Sims 3 + EA App Issues

@Brass_Buckles  The EA App doesn't always recognized owned Store content.  This is not a problem in and of itself—what matters is whether the Store site thinks you own the content.  For the Store issues, you can try a different browser in lieu of clearing Firefox's cache, or even a private Firefox window as long as you don't have any other private windows open that might be caching EA data.  Private windows don't use the browser's cache and cookies, although they do store their own until you close all of them.

For the launcher login issue and the blank Welcome page, try clearing Edge's Internet Explorer data, which is what the launcher and game use even if you don't.

https://support.microsoft.com/en-us/microsoft-edge/view-and-delete-browser-history-in-microsoft-edge-00cf7943-a9e1-975a-a33d-ac10ce454ca4

For the issue installing your expansions and stuff packs, I would suggest uninstalling the entire game, and the EA App as well, with Revo Uninstaller (the free version is fine), and reinstalling Sims 3 to a new folder you create for precisely this purpose.  The folder should be on the root level of the drive of your choice, for example C:\Games is fine, but not C:\Program Files\Games.  The EA App doesn't give a choice of where it gets installed, which is also fine.

If you have any saves or other user data you'd like to preserve, rename the Sims 3 user folder, the one you moved out of Documents > Electronic Arts, to something that doesn't include "Sims 3" in its name.  That's so Revo doesn't see it and flag it for deletion.

If this doesn't help, do any of your packs install properly, and if so, which ones do and which don't?

I had edited for length, but I did already try clearing Edge's browser cache, both for 24 hours and for all time, and it did not fix the login issue. Being on Windows 11 I don't have and can't download Internet Explorer, and I already spent so much time trying to get everything working in my game that I decided not to mess around with Firefox. That would mess up a bunch of other logins etc. that would cost me even more time to fix. Plus I'm pretty sure it wouldn't do anything since the game launcher is supposedly tied to IE/Edge, so in theory it shouldn't be tied to Firefox.

As for installing to a different drive: I already was installing on a different drive from my OS and not in Program Files, so there was no extra step there. I might return and attempt the Revo fix.

As far as saves etc. I'd already deleted all of them because I was trying to run some mods (mostly Nraas) to make the game run smoother. And no, I did not have them installed at the time of the glitch singularity. I'd already removed the mod folder at the first sign of trouble.

I don't know which expansions/packs installed and which didn't, I just know that it refused to download a certain stuff pack. I think there were more expansions and stuff packs it had not installed, but I wasn't paying attention to what had and hadn't because, I didn't expect to have any problems. And, when I did, I thought it would resume download as normal afterward, and canceled when it didn't without thinking to note which specific pack it was. In hindsight, I might've been able to restore my old Sims 3 folder and not have the login issue as well, except I'd already deleted it assuming that all would be well once it repopulated into my Documents folder. So that part is on me, but the glitch itself is not.

Most likely I'll just have to wait it out until whatever cache the data is saved in is cleared, and that'll be months or a year from now, plus it doesn't guarantee whatsoever that I'll be able to install my content again. I tried multiple times, installing it all straight from the Store and deleting duplicates so it didn't double or triple install. Not once did it show up in game, either logged in or offline mode.

It's not that the game is unplayable in the state it's in, but I paid for all this content and it shouldn't be unplayable now. What's the point in buying new settings for the game to play in, if you can't use them? What's the point in having stuff packs and expansions if they won't even download? Plus, of course I can't even try anything else at all to get my store content working if the login doesn't work. I just hope I can get my game running again before the eventual inevitable retirement of the Sims 3 store, when I won't be able to access my content anymore--since the EA app does not recognize that I own it, after all.

@Brass_Buckles  Again, if you open a private Firefox window, the data that Firefox has cached will not come into play.  That's one of the points of a private/incognito window.  And yes, the launcher does use Edge's IE mode, which is why that's the only data you'd need to clear to address launcher issues related to cached data.  IE mode data is stored separately, meaning you could clear that without deleting standard Edge data.

If you have the time and opportunity at some point, it would be worth trying to install your packs and Store data on a different computer, just to see whether this is a system issue or something on your account.  I'm not suggesting you buy another computer, only that a friend or family member might let you borrow one to test.  It wouldn't even need to be suitable for playing Sims 3: you could load the game just long enough to see whether your Store content was there and then quit again.

As an update, I haven't tried on another computer, but I just tried again and got everything but Movie Stuff installed, as far as packs. It will not install that one, no matter how many times I try. It keeps giving me a download error. I haven't tried to log in yet, I'm downloading all my content from the Store...

Except, the store insists I do not have the Pets expansion installed, although I do. It's just one glitch after another. I don't know what's gone wrong over at EA with the Sims 3 and the EA app, but I really hope they fix it. Most of these problems seem to be a server-side issue, rather than anything to do with the game or modern computer hardware and software.

Further update:

This time, most store content works without logging in (which I haven't even tried to do thanks to the problems before), except for anything relating to Pets, which despite being installed and working, the loader insists I neither own nor have installed. I'm pretty sure I bought that pack back when it released.

Despite EA Desktop saying it has an error downloading/installing Movie Stuff, the pack content seems to be present. I don't know for sure if all of it is installed, or part of it. I don't know why it keeps trying to download and install it and failing infinitely if it actually is installed. I had to cancel it in case anything else needed to download or update.

Since this is a fresh install I still think it's something to do with EA's servers and how they handle this game.

Yes, everything's working as intended now.

I couldn't install Movie Stuff because... it was already installed, which I thought might be the case since items from the pack were in my fresh install. I'm thinking that the install process must have tried installing it again after it had already installed, but I'm not sure why.

The handful of Pets-linked items from the Store, and the DJ booth that was a free preorder thing (I think) from one of the packs also finally installed. The pack had already been installed, and I own it... so I'm not sure why the installer wasn't recognizing that. At that point though I had almost everything but those few items working, so considered that a minor issue along with the weird failed efforts the app was making to install a pack it had apparently already installed. At least, it must have, because now when I check it shows a "play" button, not anything related to installing--and as I said I'd seen that items from the pack seemed to be in my game.

Thank you for fixing it, I greatly appreciate it. I probably won't be uninstalling Sims 3 for a while now, even though it takes a lot of space, just because I don't want to reinstall it again anytime soon!