Upgrading Linux Mint 18.3 to 19. Problem running LightDM

[BarkingGhostar]

I am trying to follow this guide. I enter Step 6, but after running the sudo command I am not prompted with the 8-bit selection screen:

The output from the sudo command is successful in every other way with no errors or cautions. Without this I cannot move forward and remove MDM and proceed with the LM upgrade. Ideas?

 

[BarkingGhostar]

OK, found another primer and got to the above screen, selected lightDM and removed MDM. Now installed mintupgrade and running check in Step 11. Prompted and Yes to changing repositories to LM19. Then I should be able to download and upgrade. BTW, Usually I just break out a clean SSD and install the next major version of LM freshly, but I wanted to experience the upgrade from pre-existing environment.

 

[BarkingGhostar]

OK, got LM19 installed and then it presented a one-click upgrade to 19.3, which got done. And now it presents a one-click option to go to 20. Here we go. This is so much cleaner than Windoze.