same here, I'm trying the deleting, I didn't even get a chance to downloaded everything, and the game launched fine, then I closed it to install my texture pack (Sphax ), and optifine, since my computer tends to struggle on occasion with Minecraft, especially modpacks. I spent over an hour downloading the thing, and my computer trying to lock up several times during the download, only to have it not work....It is very, very frustrating.