System settings is missing

System settings is missing. I tried reinstall it as it mentioned here, but it seems to be installed and deactivated. This problem occurred when I installed Elementary desktop environment and uninstalled it afterwards.

You can try to reinstall gnome-control-center from terminal:

sudo apt-get update
sudo apt-get install --reinstall gnome-control-center

In case you install Gnome 3.12 on Ubuntu 14.04 via the gnome3-staging ppa you need to:

sudo apt-get install gnome-settings-daemon-schemas 

This will install the settings daemon correctly. There seems to be an issue with dependencies and correct upgrade paths.