This happened to me after a fresh install of Ubuntu 15.04. It's the Unity option in Compiz settings that is disabled, but Compiz settings isn't installed by default (or wasn't for me anyway).
Easiest way to get things back to normal is to open a terminal and do: sudo apt-get install compizconfig-settings-manager then do: ccsm That will give you the Compiz settings manager and from in there you can check the box for Unity and the dash and taskbar will start. Even rebooting should keep Unity now. -- You received this bug notification because you are a member of compiz packagers, which is subscribed to compiz in Ubuntu. https://bugs.launchpad.net/bugs/1166765 Title: unity showing only blank desktop, no dash nor decorations To manage notifications about this bug go to: https://bugs.launchpad.net/compiz/+bug/1166765/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~compiz Post to : compiz@lists.launchpad.net Unsubscribe : https://launchpad.net/~compiz More help : https://help.launchpad.net/ListHelp