INFINITE LOADING BUILD MODE

@RadioactiveKlown Please do a "vanilla" test: Drag the Mods folder to the desktop, delete the file called localthumbcache, open the game to test, and exit without saving.

It loaded in without the folder. That begs to question, how do I even begin to find out what mod is breaking the game? As mentioned before I have zero mods that are script, that alter the core game mechanics, or alter the look of certain menus at all. I have over 19k mods in honesty (80% CAS), but I never download script/ UI ones since they break often. I only have standard furniture packs for my build mode and nothing that alters the gameplay. What do I do from here to fix it? 

@RadioactiveKlown Start with this list: Broken/Updated Mods & CC . Delete everything broken. Delete and redownload everything updated. Temporarily move out anything not cleared.

For non-cleared mods/CC, test in batches. Instructions are here: https://answers.ea.com/t5/Mod-CC-Issues/INFO-How-to-Use-Mods-and-CC/m-p/13439356#FiftyFifty Start with a 50-50 of your build/buy CC.

I do check that list pretty much daily, and I have none of the cc listed on it. As far as doing my cc tests in batches, considering I have almost 20k (all unsorted) mods, that seems like a very long-haul kind of task. I'll start on it eventually but I'm sure it will take days to do the constant relaunches, removals, etc. I want build mode to work but my CAS and build mode cc are all conjoined and unsorted so I'll have to do batch tests of all 19k + mods. I'll maybe remove 1k at a time and limit the relaunches to find the problem mod batch to 19. When I find out what the problem mod is, I'll come back here and add that, so if anyone else has this mod and problem they will know to delete it.

I actually have one follow-up question. I have files called BPI, SGI, HHI, MIDI sequence, TRAY ITEM, HOUSEHOLD BINARY, blueprint and room files in my mods folder. I have multiple of most. Are those safe to remove? They are not like any other mod file I have and I am hesitant to remove them on the off-chance they are important.

@RadioactiveKlown These are Tray files and do not belong in Mods. Move them to Tray (your library).

Okay! I don't know how they ended up in there. I'll start mod testing probably tomorrow, as I am working the polls today. I'll update the thread asap with the solution! 

The problems were : Pierisim had many wallpapers that broke due to the driver update/change. That as well as the "Oh My Goth- Bedroom" set by Simenapule. Pierisim claims to have fixed the issues with wallpaper, but I still had them even when redownloading his packs. I decided to download them all unmerged, so I could individually remove all the wallpaper files, and that fixed it. His CC works, just not the wallpapers. Simenapule also said they fixed their set, which I have not tested because I'm so tired of the relaunches. Maybe it works again, maybe it doesn't, but I've been at this for hours and don't care to check. 

Now I actually have a new issue. Aside from thumbnails and cc being messed up in game after the update, I now get an infinite loading screen when switching to the manage worlds map from build mode. Can't win for losing in this game— one problem fixed and another pops up. I don't know what to do. I guess that since I can access build mode now the initial issue is gone but a ton took its place. 

@RadioactiveKlown Again, 50-50 is your friend. Be sure to delete localthumbcache every time you change the Mods folder. And consider refreshing your user folder and testing only in a new save.