I forget what it said word for word, but the error message I get reads something like:
"Your save file is corrupt. Please delete it from your xbox dashboard and create a new one?"
I do have a hard drive and thats the file I always choose before playing... basically the first one on the list that pops up before playing the game. I also have two files below that with a lot less space... however I have not created any of them. Everything is default. Think one of them was cloud memory or something...