I believe I'm having the same issue. I was able to play fine for the first couple weeks and a friend and I completed the first two levels of the campaign, played some slayer and swat and also several levels of Spartan Ops with no problems. Then a couple weeks ago a started getting booted from the load screen. Now my other mates and I are getting really frustrated because they are not having the problem but I can't join them online. This is the only reason I bought the game and it won't work. I can talk to them, join a group with them but when we try to load the game I get to the point where the UNSC logo spins and it boots me to the main HALO 4 screen with the 'press start' button. Every now and then it lets me play a game of SWAT or two, and maybe the odd Spartan Ops if I'm by myself, but I don't want to play the game without being able to play online co-op with my mates. I phoned Xbox and they couldn't help, they were frustrated also and asked me to try refresh my profile, it didn't work. They said sorry and told me to write a post on the 343 forum. So here I am. I have an OPEN NAT and I don't have any issues with other games online. I have ADSL2+ and I don't want to buy a new modem or a new xbox if it's not going to fix the problem. I have one of the early WHITE xbox's but as I said it plays the game fine and all others without issues, it has just started doing this online play fault with Halo 4. I'd appreciate a reply or if someone can give me an update please??? Cheers