Hi. First of all, I am aware that there are other topics on other (and probably this forum, though I haven't found any) forums that deal with similar issues, but very few of them offer any help - including the official Sims 3 forum. I might just be looking in the wrong place, or attempted to fix my issue in the wrong way, but I was hoping that someone here might be able to help me.
I own The Sims 3 on Origin, along with these EPs:
Generations
World Adventures
Pets
Late Night
(Also the High-End Loft Stuff, but I don't think that matters)
All of these have been bought through Origin, by the way.
The issue I have is that I can only install World Adventures and High-End Loft Stuff. Every time I attempt to install any of my other EPs, the installation wizard gives me the message: "This product requires an installed copy of the Sims 3. Please install the Sims 3 before installing this product."
This is so frustrating because the error message is completely useless. Obviously the Sims 3 is installed, and I don't understand why World Adventures works just fine. I have tried uninstalling and reinstalling the game and all EPs, which hasn't worked. I can't call Customer Services for reasons I don't want to get into and I'm entirely out of ideas.
Any help is seriously appreciated, thank you in advance.