Getting rid of Unity altogether:

As per the method indicated in previous post, after installing Cinnamon, we found Unity as unnecessary. Since it has been decided not to use Unity on the desktop or laptop as we still do not have touchscreen monitor, there is no point in continuing to carry the baggage of Unity. Hence I decided to remove the Unity with this simple command in terminal (Control+Alt+T):

sudo apt-get remove unity

On next screen we added password and responded with yes. After above we decided to remove dependencies with following command:

sudo apt-get autoremove.

Problems created by solution

The above command removed some part of Unity but not entirely. On next log on Unity 2-D was still visible in the menu. Now, after reboot, there were two problems:

1. Every login took undue long period of time
2. Mounting disks had problems.
3. Some hiccups or lag time in programs

Resolution

To resolve this issue and to ensure that Unity is completely removed, searching the net produced various options. We took these bold steps. First to install a new login manager and to remove orphan packages besides installing Gnome-shell. Open a terminal and type:

sudo apt-get install gdm gnome-shell synaptic deborphan

During installation  asked to set the default Login Manager, we selected “gdm” and continue. Reboot the system to log and choose “Gnome”. We open the terminal and proceed to the removal of Unity in all its components, or open Synaptic and manually select the packages to remove:

sudo apt-get remove unity unity-2d unity-2d-common unity-2d-panel unity-2d-shell unity-2d-spread unity-asset-pool unity-common unity-lens-applications unity-lens-files unity-lens-music unity-lens-video unity-scope-musicstores unity-scope-video-remote unity-services indicator-messages indicator-status-provider-mc5 appmenu-qt appmenu-gtk appmenu-gtk3 lightdm unity-greeter overlay-scrollbar zeitgeist zeitgeist-core zeitgeist-datahub activity-log-manager-common activity-log-manager-control-center

Cleaning up other dependent packages (Do not do it):

sudo apt-get autoremove

Now here is a problem. It wants to remove braesro, firefox etc. Hence at this stage we responded with a no. Yes Abort here. Therefore some Unity files still remained but we can live with it.

Now removing the dependencies:

Now we proceed with the removal of all packages “orphans” who have remained in the Unity system with deborphan:

sudo apt-get purge `deborphan`

Take note of the quote above. It is the first character in the row of numbers, on the keyboard. We may repeat the command several times to remove even the dependencies of dependencies, until we answer that there are more packages to be removed.

Now if we try to act over enthusiastic we may try following commands (suggested on some site) to finally eliminate even the small configuration file of Unity remained, by typing: (Caution I did not fully understand the second part of this command therefore I did not execute it.)

sudo dpkg --purge `dpkg -l | egrep "^rc" | cut -d' ' -f3`

The second part ‘dpkg -l | egrep “^rc” | cut -d’ ‘ -f3’ is supposed to list the deb packages with some criterion. When executed alone on a computer with Unity duly installed, it yielded no result. Yet act with caution if choice is made in favor of executing it.

Added on 4th December 2012.

The above solution did not work. After an update, the system becomes unstable. The Update Manager keeps reminding about Unity Components, to be installed and ultimately it crashed after a few weeks.

© Sandeep Bhalla