Why won't Halo 3 load certain maps?

[Joseph W]

I've had Halo 3 since I bought my 360, and have the default campaign disc. For about a week or two, it hasn't been loading maps like Sandtrap or other maps that came with it. Now is won't even load ANY campaign maps. The disc is in very good condition.

 

[sean]

Your disk is scratch. That happened to my Halo 3 too (thats what happens you've been playing since September 25, 2007). Try borrowing the game from someone and replace the disks or buy a used copy from gamestop.