Actually, I don't know if it's called GNOME Classic. But I don't like the new GNOME (not complaining). I like the version of GNOME that was standard until a few years ago. How can I switch to that in Ubuntu 16.04?
I don't like the new GNOME
Me too, use mate. =)
Mate is a fork of "the classic gnome".
BTW plain debian does not need an external repo for this...
You can use the Gnome Classic that is built into the Gnome DE.
There is no Ubuntu Logo because you are using GDM instead of LightDM.
Just under where you enter your password is a small gear logo.
Clicking on that will give you the option to log into Gnome Classic. It runs on top of your existing Gnome 3 install but includes plugins to make it behave like the old Gnome 2.
If you select Gnome Classic it will become the default DE until you select Gnome again which will log you back into the default Gnome 3 DE.
Use Gnome Flashback. Read how to install it from here:
To install the Gnome desktop, press Ctrl + Alt + T to open a Terminal window. Type the following line at the prompt and press Enter. The line is actually two commands. The first command (before the semicolon) updates Ubuntu and the second installs the Gnome desktop.
sudo apt-get update; sudo apt-get install gnome-session-flashback
Click on the system menu in the upper-right corner of the screen and select Log Out to log out of your session.
On the login screen, click the Ubuntu icon.
A list of available desktop environments display. Select the GNOME Flashback option for either Compiz or Metacity.
You are automatically returned to the login screen. Enter your password and press Enter to log in.
Or here. It also works on 16.04.
The solution is to install MATE:
apt-get install ubuntu-mate-desktop
apt-get install mate
(note that both commands are essential)
then select MATE in the Ubuntu icon on the upper-right corner of the panel at the login screen.
The above worked in Ubuntu 15.10 also.
This answer was extracted from the OP's edit to the question -- please don't add the answer to the question, that's what the self-answer box is for :)