Performing a Hard Reset procedure on the XBox One can help to fix the following issues:
Kinect won't register voice.
Unable to sign-in to Xbox Live.
Games are not launching.
The Hard reset procedure is achieved by clearing the system cache,of your console. On the Xbox 360 you simply have to go to Settings > System Settings > Storage > Clear System Cache.
This option is not available on the Xbox One!
To clear the cache of the Xbox One, simply press and hold the Power button for couple of seconds until the screen goes off.
Wait a couple of seconds and restart your Xbox One.