I just updated my kernel to 4.4.0-96-generic, and my external USB devices (HDD, flash drive, printer) are no longer being automounted.
Prior to the update, when I logged in, the devices would show up as icons in my launcher bar. I would be able to click on the icon and a "Files" window would open and I would be able to navigate the directory structure. Now, nothing happens.
The devices are visible in "Disks." (gnome-disks)