hello, i had the same problem in hardy but i solved it from this link http://ubuntuforums.org/showthread.php?s=e0cafa9e0ceb48eaf29cae2a4edcc855&t=723361
-- update-manager fails to bring up the password prompt for root privileges https://bugs.launchpad.net/bugs/187982 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs