ugh I am having the exact same problem and it sucks. I didn't realize if i have no mods running that it works, but just like the OP, if I disable all mods, the game works, but I could not play my previous game, I had to start a brand new game (probably because my previous save was using about 100+ mods). However upon doing this I noticed that the skyrim.esm aswell as update.esm are not in the list of mods. So I guess the connection I'm making is that the game only registers these esms if nothing else is there, but the second another mod is activated it is loaded before these, causing CTDs on game startup. I'm certainly no wizard at this stuff, so maybe bethesda patched the game so that these don't show up in the list anymore since people were screwing with these 2 esm load orders. IF someone can please help, it would be very appreciated, I basically just revamped my entire skyrim and wwant to play with all my sweet new addons! Edit:Just wanted to note I've got over 500 hours in skyrim play time, a lot of which was modded. It just randomly stopped working after I had downloaded a few different things such as 2k texture, game boost, but these were working fine, things didn't get screwy until I downloaded skyboost and since then its just been CTDville. Edit V2:Okay so I deleted the skyrim.esm and update.esm, let steam download them again, and now I can setup mods and run the game. However, when I go to start a new game, the game doesn't freeze or crash, the menus disappear, but the new game never actually starts up..This has to be the most confusing thing I've ever encountered. Hopefully this is narrowing it down some. Trying to load previous saves still results in CTD. I really don't care about starting over again, but I do want to be able to use my mods obviously. So if anyone has a solution, me and I'm sure the OP would really friggin appreciate the help.