I can't finish the campaign on Legendary

I can’t play the mission Forerunner on Halo 4 and I’ve went to settings on my X-Box, put in disc two and downloaded it again, and it still won’t work!

> I can’t play the mission Forerunner on Halo 4 and I’ve went to settings on my X-Box, put in disc two and downloaded it again, and it still won’t work!

Reinstalling disc 2 wont do much good, since it is just the multiplayer portion of the game. The campaign content is located on disc 1, and since you are having trouble loading a mission is could be a slight scratch on your disc. Check the disc for any dirt or damage (even the slightest could cause a problem). If the problem persists, try another copy of the game from a friend and play the mission that way. If your friends copy works ok, then you have a problem with your disc.