First, I have been playing TS3 forever. I do know how the CC framework works. So without intending to offend anyone, I don't need a tutorial on how to work the mod folder or resource.cfg

My problem: I installed Windows 8.1 and used it for 3+ months. Yesterday I missed TS3 and installed it again from Origins. TS3 no longer recognizes any CC. I checked everything, the mod folder is in place (in Electronics Arts/The Sims 3/Mod) as usual. Resource.cfg has no change. TS3 behaves like there is no CC installed.

I checked everything. None of the NRAAS mod shows up. None of custom skin shows up. Even the skipped intro mod doesn't work (TS3 plays full intro). None of the clothing, furniture CC showed up. I start to wonder what Windows 8.1 has anything to do with TS3. I checked Google, it seems there is no change from Windows 7 (my original OS) to Windows 8.1.

Does anyone know what I may have checked off that causes TS3 to ignore CC? FYI: Store content works.

What is wrong with Windows 8? Or windows 8 + TS3?

*wonders about the game being correctly patched*
*wonders about cache files*

I reinstalled the game. It is brand new. There should not be cache issue. The game is fully patched as well coming from Origins. I don't think I can even install the game in earlier version.

Did you ever get this figured out? I have this problem now too. It was working fine then all of a sudden it no longer loads the mods at startup.

Windows 8 has One Drive. It's not as insistent as Windows 10 seems to be that when your program says "Documents" it means the One Drive Documents , but it can happen.
Look in One Drive for an Electronic Arts folder. If it's there, it shouldn't be. Disable One Drive before playing the Sims, and put everything from One Drive back where it is supposed to go. (A lot of it, if not all of it, can go into the recycle bin if you've already had the game reading your Documents folder on your own hard drive, especially if you haven't created a sim, built a lot, or saved a game while the CC is missing.)