I can confirm this bug. It actually broke my dist-upgrade from 12.04 to 14.04. I fixed it manually by deleting the broken script and removing gdm.
I tried to reinstall gdm today but the package is still broken, i. e. the post-install script is broken. Executing it manually with bash -x /var/lib/dpkg/info/gdm.postinst results in: + set -e + . /usr/share/debconf/confmodule ++ '[' '!' '' ']' ++ PERL_DL_NONLAZY=1 ++ export PERL_DL_NONLAZY ++ '[' '' ']' ++ exec /usr/share/debconf/frontend /var/lib/dpkg/info/gdm.postinst Use of uninitialized value $action in string eq at /usr/share/debconf/frontend line 27. -- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to gdm in Ubuntu. https://bugs.launchpad.net/bugs/1310718 Title: package gdm 3.10.0.1-0ubuntu3 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gdm/+bug/1310718/+subscriptions -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs