How to remove Pantheon DE from Ubuntu 16.04?

Can anyone help me remove elementary-desktop? I installed it in my Ubuntu 16.04 LTS x64 system. I already did the "solution" from this question:
How to completely remove Elementary-Desktop from Ubuntu 14.04
and also

sudo apt-get purge elementary-desktop elementary-icon-theme elementary-theme elementary-default-settings

still no luck. I also did

sudo apt-get autoclean elementary-desktop

still didn't do the job. It's still in my system, "elementary OS Desktop" is written in my bar, plus it could still be selected during login.

Btw, I just followed the installation here: How do you install Pantheon on Ubuntu 16.04?

2 Answers

You used dist-upgrade to install Elementary DE. By doing so, you installed PPA provided versions of packages over standard Ubuntu versions. For example, if Ubuntu provides a nautilus package, and those PPAs provide another nautilus package with higher version, you installed that one.

That's why only removing extra elementary packages such as elementary-desktop, elementary-icon-themes is not sufficient. You have to remove those patched packages too!

So, to completely remove elementary effect, you must go back to Ubuntu versions of packages. To do so, you need ppa-purge. Because only (as a tool to do these things) ppa-purge downgrade packages from PPA versions to Ubuntu versions.

Use these (Change the list according to your usage of PPAs)

sudo ppa-purge ppa:elementary-os/daily
sudo ppa-purge ppa:elementary-os/os-patches
sudo ppa-purge ppa:elementary-os/testing
sudo ppa-purge ppa:mpstark/elementary-tweaks-daily
sudo ppa-purge ppa:elementary-os/stable

To completely get rid of elementary things.

If you don't have ppa-purge already installed, install using

sudo apt-get install ppa-purge

Note 1: If you already removed those PPA repository either using sudo apt-add-repository -r or manually editing files, re-add them. Because ppa-purge needs those package list to do the downgrading. After re-adding them, use

sudo apt-get update

command to refresh package index.

Note 2: If you are having an error from ppa-purge saying it can't find aptitude use

sudo apt-get install aptitude

to install it.

Note 3: If ppa-purge fails for some PPAs not being available, remove those PPA entries manually. ppa-purge won't work if every repository doesn't work.

Note 4: If some of PPAs are disabled now (after installing package from them), you have little luck downgrading them automatically. You can identify them and manually downgrade them using synaptic or aptitude. But it's a tedious job.

Note 5: If you still see Elementary session listed on Lightdm, remove pantheon-session package manually.

Notes 6: Remove every extra packages you can identify installed from those PPAs but not available in Ubuntu repositories.

I just did it with

sudo apt-get autoremove --purge elementary-desktop