I came across many users who had this issue and below are some links that are related to my issue but I still cant figure it out. Its really annoying I have tried everything from factory reset to disabling any light app to restarting the phone nothing seems to work! I even tried downloading a new file explorer app as someone mentioned to try that and still no result. The problem is its disabled and there is no way I can move it to enable. I tried downloading an APK file and when I click to install it, a screen pops saying I need to uncheck the 'allow install unknown apps'. I'm having an issue with my Samsung Galaxy Note fan edition.