If it is the E200 error with an EF in the second set of numbers I just fixed this this morning. I unplugged my Xbox One at work this morning without powering it down. When I arrived home it had the error message when I turned it on. Its going to sound bad but the easiest way to resolve for me was to just bite the bullet and do the factory reset option in the offline system update diagnostic tool. Cross your fingers and hope you have been connected to the server recently and you don't have any digital only games installed (I had one half installed so I was not worried) I sincerely hope this helps anyone out there experiencing this error message. If it does not then I heartily apologize