Blank display on installing Kubuntu

Problem

I had a computer with Ubuntu 16.04 running the Unity desktop. I wanted to switch to Kubuntu, so I installed it using this command:

$ sudo apt install kubuntu-desktop

Everything installed fine, except this error at the end:

kde-telepathy-minimal : Depends: kde-config-telepathy-accounts (>= 0.9.0) but it is not installed

After this, there is an error about kaccounts-provider whenever I login into Unity. If I try to login into the KDE desktop, I get a blank display!

Solution

This error seems to be hitting lots of people as seen here. This seems to be caused by a conflict between packages required by Unity and KDE. Apparently, Unity (Ubuntu) and KDE (Kubuntu) cannot be installed on the same computer!

Following some clues given by other users, I forcefully removed Telepathy since I did not need it anyway:

$ sudo dpkg --remove kde-telepathy
$ sudo apt update
$ sudo apt dist-upgrade

After this the Unity error on login and the black display in KDE went away. I was able to switch to using KDE as my primary desktop.

So, if you intend to use Kubuntu, you are better off installing a Kubuntu ISO directly instead of installing it from inside Ubuntu.