Never had this happen to me and I've never known any of my friends going through this. Not sure what causes it aside from it being a bad disc

Sorry to hear about the situation with your copy of Modern Warfare 3.  What console are you playing the game on?  Also is there any damage on the game disc itself.

If its for Xbox 360, try and clear the system cache or install the game disc to your hard drive.

If its for PlayStation 3, I recommend removing the game data file and re-downloading the update and DLC.

You can find both instructions here:

https://support.activision.com/articles/en_US/FAQ/Clearing-the-Xbox-360-System-C ache-or-PlayStation-3-Game-Data/?q=clear+system+cache&l=en_US&c=Game_Title%3AAll &fs=Search&pn=1

Now if the problem continues, try testing your disc out on another console if possible.  This will allow us to see if we can replicate the issue.  Keep us posted.  Thanks!^RT

I bet your system scratched the **** out of the disc. It happened to me too, I just got it resurfaced for 3 dollars at a gamestore.