I was trying out different desktop environments on Ubuntu 16.04 LTS and ran sudo apt install ubuntu-mate-desktop. It worked, but when I restarted my computer Ubuntu MATE took over start up and the login screen. After uninstalling ubuntu-mate-desktop nothing changed, so I ran sudo apt purge --auto-remove mate* and sudo apt purge --auto-remove *mate*. Now there is no loading screen when shutting down or starting up, and the login still has the layout from Ubuntu MATE.
How can I revert the start up and login back to Ubuntu default?
Edit: I tried tried the accepted response from the question Getting back Ubuntu's default boot splash. This got the splash screen back, but the login screen still has the Ubuntu MATE default not including the background. I also ran sudo apt install ubuntu-desktop, but that didn't do anything because it is already installed.
For more detail, startup appears slower, especially getting into the default DE from the Ubuntu MATE login. Once in the default DE, after timeout it goes to the default login, but if I logout it goes to the Ubuntu MATE login.
