updated any of them? -try using TESVedit to see if there is any missing masters although, if you really didn't touch a thing, I doubt you will find any. -if you have any enb try disabling it and see if that solve the problem. -if none of the above works launch a new game with the same mods--->works? your save is corrupted (probably) --->doesn't work? try launching this game with no mods:---> works now?try reenabling your mods by small groups until you find the one responsible. ---> still doesn't work? check your local files with steam - altternatively you could try enabling logs from the .ini, launch the game again and then post the .txt file hoping that someone can help you with it because I am unlikely to understand it.