I have seen plenty of people asking about this on the forums and coming to the Xbox ambassador support group. I myself have been having the problem of “Downloading latest MP data”
Here is a list of everything I have done to try and fix it.
•Cold Start
•Deleted profile
•Cleared presistent storage
•Restarted wirless router
•Tested wired connection
•Cleared Mac address
I don’t know if they are any fixes as of yet. I have heard that completely deleting you game and re-installing it works, but to be honest mine is digital and it would take a week to download it and not to mention I would go over my data plan. <- This is not an option for me and I’m sure many others feel the same way.
*This post is not to harm 343i, Microsoft, Xbox live and any of there employees.