Exact same problem on my Toshiba L300D system running 12.04. An update icon appears showing upgrades available but icon does not respond if clicked. Current workaround is to kill update-manager and relaunch it from a terminal.
Exact same problem on my Toshiba L300D system running 12.04. An update icon appears showing upgrades available but icon does not respond if clicked. Current workaround is to kill update-manager and relaunch it from a terminal.