in my case it happens when i am trying to install it as user root when upgrading per "sudo aptitude dist-upgrade" it worked.
-- package gdm 2.28.0-0ubuntu8 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1 https://bugs.launchpad.net/bugs/438789 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
