Setup – Dell Latitude 7490 running Ubuntu 18.04 Bionic and Dell WD15 USB-C dock.
Problem – system freezes when dock unplugged.
This problem started after updates. The solution found was to revert to the previous kernel (
4.15.0-44-generic. Did this by setting GRUB to remember the boot setting – change
Then hit esc at the loading screen to get to the grub menu.