i think i might of found a fix testing now, try verifying your game integretity by go on your steam, right click MW:3, go on properties > Local Files > Verify Local Files (of it might be Verify Game cache) cant remember its name. I am having the same problem ill get back to u if it works
---------- Post added at 09:25 PM ---------- Previous post was at 09:23 PM ----------
worked
read above