Forum:Difficulty issue

So, I have played through the first game many times. I have beaten Vet and Hardcore difficulties in the past, and have the achievements to show for it. I went to start a new game on Insanity. Set the difficulty on the main menu. Part the way through, it seemed too easy, so I checked the options, and I was on Vet. Both Hardcore and Insanity are locked again. I've tried all kinds of things, but it's still locked. I really don't want to play through two more times just to unlock Insanity again. Is there any way to fix this?