Not sure whether this is of any help to you. I encountered the same symptoms and discovered that the problem stemmed from the permissions of /etc/pam.d/common-password being incorrectly set to 600 when it should be 644. Looking at /var/log/auth.log should confirm or deny whether yours is the same issue.
-- gnome-screensaver-dialog never shows up https://bugs.launchpad.net/bugs/146412 You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is the registrant for gnome-screensaver. -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
