[AC Question]

I have downloaded updated drivers, and tried chatting with a Samsung representative only to find she can't solve my issue because I am not in the USA

[B. Diddy]

Welcome to Android Central! Is this where you downloaded the USB driver from? Download Center: Download Software, Firmware, Drivers & Manuals | Samsung

Have you tried a different USB cable? Cables can fail unexpectedly. Also try using a different USB port on the computer, if possible.

[feske]

Having same problem help just randomly too... will charge from pc (using 3 different cables to are samsung)

[feske]

verizon?

[B. Diddy]

If different cables and different USB ports didn't work, and you're sure you have the latest USB driver installed, then it's possible the microUSB port is faulty. You might have to bring the phone to a repair shop. Have you tried connecting to different computers?

[clickerman]

I would bet that the USB port or the USB card is defective. I had to replace my USB card about 6 months ago.

[anon8380037]

Are you trying to read folders using Windows Explorer, or are you using Kies.
I read that Lollipop may not be, or will not be compatible with Samsung Kies on a pc, as they are switching people to the revised Smart Switch pc program. Try downloading Smart Switch to your pc, and Kies if you don't have it.
You cannot copy media files across to Smart Switch like you could with Kies, but it should install the correct drivers and you can use Windows Explorer to access DCIM folders and others when the S4 shows as a Portable Media Device.

(You won't need the associated Smart Switch app, as it only helps to transfer data from an old device to a new Samsung (what Smart Switch only did originally).

Let us know if any of that works.