I restarted Unity and that worked for me.
Press Ctrl-Alt-T and that will bring the terminal window up.
This will restart it:
dconf reset -f /org/compiz/
unity --reset-icons &disown
This did not work for me. I am an ubuntu noob and only use to play/learn. I have a snapshot before installing tools I am using til this is figured out.
peter@ubuntu:~$ unity --reset-icons &disown
[1] 2989
peter@ubuntu:~$ Killed
unity-panel-service: no process found
Checking if settings need to be migrated ...no
Checking if internal files need to be migrated ...no
Backend : gconf
Integration : true
Profile : unity
Adding plugins
Initializing core options...done
Initializing composite options...done
compiz (core) - Error: Couldn't load plugin '/usr/lib/compiz/libopengl.so' : libGL.so.1: cannot open shared object file: No such file or directory
compiz (core) - Error: Couldn't load plugin 'opengl'
compiz (core) - Error: Couldn't load plugin '/usr/lib/compiz/libcompiztoolbox.so' : libGL.so.1: cannot open shared object file: No such file or directory
compiz (core) - Error: Couldn't load plugin 'compiztoolbox'
compiz (core) - Error: Couldn't load plugin '/usr/lib/compiz/libdecor.so' : libGL.so.1: cannot open shared object file: No such file or directory
compiz (core) - Error: Couldn't load plugin 'decor'
Initializing vpswitch options...done
Initializing snap options...done
Initializing mousepoll options...done
compiz (core) - Error: Couldn't load plugin '/usr/lib/compiz/libresize.so' : libGL.so.1: cannot open shared object file: No such file or directory
compiz (core) - Error: Couldn't load plugin 'resize'
Initializing place options...done
compiz (core) - Error: Couldn't load plugin '/usr/lib/compiz/libmove.so' : libGL.so.1: cannot open shared object file: No such file or directory
compiz (core) - Error: Couldn't load plugin 'move'
compiz (core) - Error: Couldn't load plugin '/usr/lib/compiz/libwall.so' : libGL.so.1: cannot open shared object file: No such file or directory
compiz (core) - Error: Couldn't load plugin 'wall'
compiz (core) - Error: Couldn't load plugin '/usr/lib/compiz/libgrid.so' : libGL.so.1: cannot open shared object file: No such file or directory
compiz (core) - Error: Couldn't load plugin 'grid'
Initializing session options...done
Initializing gnomecompat options...done
compiz (core) - Error: Couldn't load plugin '/usr/lib/compiz/libanimation.so' : libGL.so.1: cannot open shared object file: No such file or directory
compiz (core) - Error: Couldn't load plugin 'animation'
compiz (core) - Error: Couldn't load plugin '/usr/lib/compiz/libfade.so' : libGL.so.1: cannot open shared object file: No such file or directory
compiz (core) - Error: Couldn't load plugin 'fade'
compiz (core) - Error: Couldn't load plugin '/usr/lib/compiz/libunitymtgrabhandles.so' : libGL.so.1: cannot open shared object file: No such file or directory
compiz (core) - Error: Couldn't load plugin 'unitymtgrabhandles'
compiz (core) - Error: Couldn't load plugin '/usr/lib/compiz/libworkarounds.so' : libGL.so.1: cannot open shared object file: No such file or directory
compiz (core) - Error: Couldn't load plugin 'workarounds'
compiz (core) - Error: Couldn't load plugin '/usr/lib/compiz/libscale.so' : libGL.so.1: cannot open shared object file: No such file or directory
compiz (core) - Error: Couldn't load plugin 'scale'
compiz (core) - Error: Couldn't load plugin '/usr/lib/compiz/libexpo.so' : libGL.so.1: cannot open shared object file: No such file or directory
compiz (core) - Error: Couldn't load plugin 'expo'
compiz (core) - Error: Couldn't load plugin '/usr/lib/compiz/libezoom.so' : libGL.so.1: cannot open shared object file: No such file or directory
compiz (core) - Error: Couldn't load plugin 'ezoom'
compiz (core) - Error: Couldn't load plugin '/usr/lib/compiz/libunityshell.so' : libGL.so.1: cannot open shared object file: No such file or directory
compiz (core) - Error: Couldn't load plugin 'unityshell'
Setting Update "main_menu_key"
Setting Update "run_key"