So it seems gdm is buggy there, the prerm sets the default to "lightdm" rather the to "/usr/sbin/lightm", lightdm has a similar bug since its script is copied from gdm...
** Also affects: gdm (Ubuntu) Importance: Undecided Status: New ** Changed in: gdm (Ubuntu Oneiric) Importance: Undecided => High ** Changed in: gdm (Ubuntu) Importance: Undecided => High ** Changed in: gdm (Ubuntu Oneiric) Status: New => Incomplete ** Changed in: gdm (Ubuntu) Status: New => Incomplete ** Changed in: gdm (Ubuntu) Status: Incomplete => Opinion ** Changed in: gdm (Ubuntu) Status: Opinion => Confirmed ** Changed in: gdm (Ubuntu Oneiric) Status: Incomplete => Confirmed ** Changed in: gdm (Ubuntu Oneiric) Status: Confirmed => Triaged ** Changed in: gdm (Ubuntu) Status: Confirmed => Triaged ** Changed in: lightdm (Ubuntu) Status: Confirmed => Triaged ** Changed in: lightdm (Ubuntu Oneiric) Status: Confirmed => Triaged -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to lightdm in Ubuntu. https://bugs.launchpad.net/bugs/864174 Title: boot hangs waiting for lightdm after purging gdm (wrong default- display-manager) Status in “gdm” package in Ubuntu: Triaged Status in “lightdm” package in Ubuntu: Triaged Status in “gdm” source package in Oneiric: Won't Fix Status in “lightdm” source package in Oneiric: Won't Fix Bug description: I've installed Oneiric beta2 and at some point installed and purged gdm. After that, boot will hang waiting for lightdm to start, which never happens. This is because /etc/X11/default-display-manager ends up saying "lightdm" whereas /etc/init/lightdm.conf accepts "/usr/bin/lightdm" or "/usr/sbin/lightdm". The user sees the splash screen messages "Waiting for up to 60 more seconds for network configuration" and "Booting system without full network configuration". However, the fix is to edit the contents of /etc/X11/default-display- manager to read "/usr/sbin/lightdm". ProblemType: Bug DistroRelease: Ubuntu 11.10 Package: lightdm 1.0.0-0ubuntu4 ProcVersionSignature: Ubuntu 3.0.0-12.19-generic-pae 3.0.4 Uname: Linux 3.0.0-12-generic-pae i686 ApportVersion: 1.23-0ubuntu2 Architecture: i386 Date: Sat Oct 1 19:56:46 2011 SourcePackage: lightdm UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gdm/+bug/864174/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp