For years with my Note4, then my Note5, I used Samsung's PC app called Smart Switch to USB-connect to my phone. Initially, it gave me a choice which included "File Transfer" and later, it simply defaulted to that function. And "CELL PHONE" would pop up in Windows 10 File Explorer. I could copy/paste to and from the phone's memory. All of a sudden, this functionality has disappeared! All I get on the phone is "Charging." I don't know if I accidentally changed a setting or if an Android update changed this. I do keep the phone up to date with all Android updates.