I know that a lot of us are having issues with playing co-op and losing saved progress. To help the kind folks at 343 I figured that we could start a thread and post info such as:
Xbox 360 Type: Slim or Fat
Co-op: Yes or No if so Local or via Xbox Live
When you were playing co-op were you using the Preview dashboard update or an older version?
What kind of storage were you using? Memory unit or HDD (Hard Disk Drive)
What kind of internet connection were you using wireless or wired?
I know this sounds like some work to post but this could really help 343 Isolate the issue and get a patch for those of us having the issue!
> Fat
> New Dashboard
> Co-op Via Xbox Live (Slightly Laggy yet I have Open Nat and Fast Connection ‘possibly the games slow?’)
> Wireless
When I play co-op via split screen local I encounter choppiness/lag whatever you want to call it as well. I experienced it with the game Installed as well as not installed to the HDD.