[ubuntu 14.04]ubuntu-desktop 설치시 dependency 에러

sudo apt-get install ubuntu-desktop  

Error :

ubuntu-desktop : Depends: ubuntu-session but it is not going to be installed
                  Depends: unity-control-center but it is not going to be installed
                  Depends: unity-settings-daemon but it is not going to be installed
                  Recommends: xul-ext-webaccounts but it is not going to be installed
E: Unable to correct problems, you have held broken packages.

 

-->

sudo apt-get install gnome-settings-daemon-schemas=3.8.6.1-0ubuntu11.2
sudo apt-get install ubuntu-desktop