Files (used to) appear on smartphone but not on Windows Explorer
Make sure External Storage and Media Storage are running .
Rescan SD Card! Add the path to your SD and scan (Usually something like /sdcard or /storage/****-**** ). Reboot...
If second doenst work you could try: adb Guide or adb Driver :


On your phone: 

Enable Developer Options on your phone -> Enable
 USB-Debugging -> Plug-in USB-cabel

On your PC:

Windows: Windows Key + R -> cmd ->  adb devices: 

List all available devices:
Something like:

List of devices attached
9cc74efc        device


If you see your device :

adb root &amp;&amp; adb shell

am broadcast -a android.intent.action.MEDIA_MOUNTED -d file:///sdcard


Source