How to Turn Off Unknown Sources for Android Phones

1. Tap the 'Applications' icon on the home screen of your Android phone, scroll to 'Settings,' and touch the icon or press the 'Menu' key on the phone and tap 'Settings.'

2. Touch 'Applications.'

3. Tap 'Unknown Sources' if it has a green check in the check box. Press the 'Home' key to return to the Android home screen.