Unity (Ubuntu) option is missing from login menu

After purging and reinstalling Nautilus, Unity is missing and everything defaults to GNOME Classic. The Unity (Ubuntu) option at login is even missing. The Unity plugin is still ticked in ccsm. If I run unity --replace the terminal starts Unity and I get the dash and Unity panel but still have the bottom GNOME panel. If I log out and back in everything is back to GNOME Classic. It seems the only way I can run Unity is by running unity --replace in the terminal.

Is there a way to get things back to normal without a clean install?

Solution 1:

Most likely you removed some packages that depend on Nautilus but did not reinstall them.

Make sure that the package ubuntu-desktop is installed, for example by running

sudo apt-get install ubuntu-desktop

in a terminal.