Restoring your device to default settings helps when the device crashes and resets itself or when apps freeze/hang or reset the device.
Performing these steps resets all system settings (e.g. ringtones, sound settings, display settings, etc.) back to their default values. Personal data, such as downloaded apps and media (pictures, videos, music), aren't affected.
From a Home screen, touch and swipe up to display all apps.
Navigate: Settings > System > Reset options .
Tap Erase all data (factory reset).
Review the info then tap RESET PHONE.
If presented, enter the current PIN or pattern.