Okay so I had this error message like a lot of people have (if you haven’t you’re lucky as hell). Okay so you log into halo and get a dreaded “Profile Sync Error” and all of your armour is gone and everything else. Don’t panic! There are a few fixes online but none of them worked for me this may work for you! Simply go to your settings>network settings>disconnect Xbox from internet. After it disconnects simply reconnect to your desired connection and presto! This at least worked for me hope it helps!