Ubuntu 18.04.1 LTS issue with Dell Thunderbolt 3 Dock after update [duplicate]

I am posting to confirm I had this same issue after a kernel update yesterday.

Same symptoms, wouldn't boot with the dock plugged in. Plugging the dock in after laptop boots standalone caused the laptop screen to go black and everything lock up.

Tried with everything disconnected from the dock except power (as I thought the laptop was having issues going to the dual monitors).

Had to roll back from linux-image-4.15.0-44-generic (4.15.0-44.47) to linux-image-4.15.0-43-generic (4.15.0-43.46) and the Dell dock + monitor is working for me now.

Solution

Press ESC on boot (UEFI) or Left Shift if BIOS, then select advanced boot options. I went to older kernel (-43). Confirmed issue wasn't occurring for me on -43, so removed -44.

sudo apt-get purge linux-image-4.15.0-44-generic

Upgrading kernel to 4.15.0-45 (available today on Ubuntu repositories) solved if for me! At last!