I was getting the Microsoft Live - Xbox 360 gamer profile error 80154042 whenever I tried to change my account I'd followed the associated account instructions and knew I'd done everything correctly but still got: "Can't retrieve information from Xbox Live, please try again later. Status code 80154042."

Basically it seems the error 80154042 means you're signed in somewhere else, phone, computer, surface wherever just somewhere else, all I had to do was shut down my laptop and that took care of the error!

I wish Microsoft just said "this account is signed in on another device" rather than giving an error code which takes forever to find out about!