I can open the game, but it gets stuck on the 'The Sims 4' and the copyright underneath it, before the maxis animation thing.
It was working fine before
I recently downloaded some (well, alot) cc which was inbetween working and not working.
Then it's probably something you downloaded and you need to find out what it is.
Use the 50/50 Method: http://simswiki.info/wiki.php?title=Game_Help:Finding_Problem_Custom_Content
You don't need to add those back.
Put back your saves folder, your mods folder (one by one), your Tray folder and if you have screenshots, custom music or recorded videos those too.
That's about all you need. The rest is just cache stuff that recreates
This has an explanation what files are for what: http://sims4.crinrict.com/en/2014/09/user-files-explained/
That's a bit weird since those are just text files that give info about crashes but as long as it works, all good, right ?
