Why doesn't my PC recognize my device?

[mhubel]

After the last update, the phone shows up on a PC as an empty device, even if the screen is unlocked. Updating drivers has not helped. There does not seem to be a "media device" option anywhere. Is a transfer directly to/from a PC still possible?

[tikibar1 · Accepted solution]

With the Marshmallow update, the default USB mode is charging only.  Once you connect the phone and computer with the USB cable, pull down the notification shade, tap where it says USB Charging, and change it to File Transfer.