Unfortunately I can't give you any better, direct advice :( .
Tell me - are you able to see log in window when opening Xbox One app? Or does it throw error, that it can't connect? How about the...

Please check the sate of Storage Service under services.msc (WinLogo+R and type services.msc - you will see Services Controller). I got exactly the same problem because Storage Service was disabled...

Hi,
I only registered to say BIG THANK YOU. I don't know why Storage service was completely disabled on my PC, but I've seen also other services that weren't properly configured after Windows 10 RS1...