@Dagamanama Please post screenshots of the contents of the Packages and Overrides folders, as in, I'd like to see the files themselves.
Keep in mind that the mod list at the Main Menu only includes script mods, and perhaps core mods with scripted components. Tuning mods and any custom content won't show up.
Screenshots of the packages and overrides folder
@Dagamanama It looks like almost all of your .package files are custom content, not mods, so they wouldn't show up at the Main Menu. For the ones in Overrides, most of those look to be default replacements for existing in-game items. So they wouldn't show up as additional items, they'd overwrite what you already have.
Additionally, if you don't own the packs in question—you can see that most of these items have mention a pack in their names—the items won't load at all. Let me know which expansion and stuff packs you own and whether the items associated with those packs are loading in-game. For example, if you don't have Seasons installed, the items with EP8 in their name wouldn't show up either.
Finally, please delete the cache files every time you quit, at least while you're troubleshooting.
@puzzlezaddict My problem was that although I had the overrides installed, they wouldn't show up in the game (it would still use the standard content and not the overrides). And I had all the EPs installed. But now I managed to fix the problem myself...
I realised that my graphics settings were pretty low. I set them to maximum and suddenly the overrides worked! Nevertheless, thank you very much for your help!!
@Dagamanama That doesn't make any sense unless none of the overrides included a low LOD model. And that would itself be odd. Still, glad you got it fixed.
