I tried what @alfieralphie mentioned earlier in this thread and now my game will at least start (albeit slowly), and the pack does show as installed in-game but not in origin. I'm hopeful.
Renaming the Sims 4 folder is the same as moving it to the desktop (which I think you already tried?) as it forces the game to create a new, clean Sims 4 folder so I wonder if uninstalling and reinstalling Origin helped you?
@Bluebellflora I think it was renaming it that helped because previously I had reinstalled origin but had only removed the mods folder.
Ah ok. Interesting - thanks!
