I don’t know if this has happened to anyone else but every time I’ve been playing online i keep on getting disconnected from XBL. I have tested my connection and xbox with other games but this only happens with Reach.
Try resetting your modem/router if you use one.
When you start Reach what are your network stats?
Is your NAT open?
Have you got bad bandwidth or something?
Wired or wireless?
If you’re on wireless, I highly recommend going wired.
I’ve reset my hub, nat etc is excellent and i have tried wired it has not happened on any other game could i have been hacked by a miffed off player?