GDM doesn't start on boot

[أحمد المحمودي (Ahmed El-Mahmoudy)]

I've install Ubuntu GNOME 14.04 on a machine, and when it boots, it remains stuck on plymouth animation screen.
When I press CTRL+ALT+F1, I can login from tty1.
When I checked the :0-greeter.log I found some bunch of errors.

From the terminal, if I run: 'sudo restart gdm', gdm starts, and :0-greeter.log doesn't have errors.

Log files will be attached.
---
ApportVersion: 2.14.1-0ubuntu3.2
Architecture: amd64
CurrentDesktop: GNOME
DistroRelease: Ubuntu 14.04
Package: gdm 3.10.0.1-0ubuntu3
PackageArchitecture: amd64
ProcVersionSignature: Ubuntu 3.13.0-29.53-generic 3.13.11.2
Tags: trusty
Uname: Linux 3.13.0-29-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups:

_MarkForUpload: True
---
ApportVersion: 2.14.1-0ubuntu3.2
Architecture: amd64
DistroRelease: Ubuntu 14.04
Package: gdm 3.10.0.1-0ubuntu3
PackageArchitecture: amd64
ProcVersionSignature: Ubuntu 3.13.0-29.53-generic 3.13.11.2
Tags: trusty
Uname: Linux 3.13.0-29-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups:

_MarkForUpload: True
---
ApportVersion: 2.14.1-0ubuntu3.2
Architecture: amd64
DistroRelease: Ubuntu 14.04
Package: gdm 3.10.0.1-0ubuntu3
PackageArchitecture: amd64
ProcEnviron:
 LANGUAGE=en_US:
 TERM=linux
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 3.13.0-29.53-generic 3.13.11.2
Tags: trusty
Uname: Linux 3.13.0-29-generic x86_64
UpgradeStatus: Upgraded to trusty on 2014-05-11 (31 days ago)
UserGroups:

_MarkForUpload: True

[Tim Lunn (darkxst)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. Please execute the following command, as it will automatically gather debugging information, in a terminal:

  apport-collect 1328820

When reporting bugs in the future please use apport by using 'ubuntu-bug' and the name of the package affected. You can learn more about this functionality at https://wiki.ubuntu.com/ReportingBugs.

[أحمد المحمودي (Ahmed El-Mahmoudy) (aelmahmoudy)]

apport information

[أحمد المحمودي (Ahmed El-Mahmoudy) (aelmahmoudy)]

apport information

[أحمد المحمودي (Ahmed El-Mahmoudy) (aelmahmoudy)]

The previous apport is after the gdm restart.

[أحمد المحمودي (Ahmed El-Mahmoudy) (aelmahmoudy)]

apport information

[أحمد المحمودي (Ahmed El-Mahmoudy) (aelmahmoudy)]

apport information

[أحمد المحمودي (Ahmed El-Mahmoudy) (aelmahmoudy)]

The previous apport is after the reboot. (before gdm restart)

[أحمد المحمودي (Ahmed El-Mahmoudy) (aelmahmoudy)]

The machine has an Intel GPU

[أحمد المحمودي (Ahmed El-Mahmoudy) (aelmahmoudy)]

Funny thing, I installed lightdm (with --no-install-recommends), and tried it, but it won't work. It wouldn't even start manually.

Anyways, after I removed lightdm and then rebooted. Now gdm starts on boot.

[أحمد المحمودي (Ahmed El-Mahmoudy) (aelmahmoudy)]

apport information

[أحمد المحمودي (Ahmed El-Mahmoudy) (aelmahmoudy)]

The previous 4 comments are from another machine that was upgraded from Ubuntu 12.04.4 to Ubuntu 14.04, then I installed: ubuntu-gnome-desktop & removed ubuntu-desktop to convert to Ubuntu GNOME.

lightdm runs on this machine. But gdm would not start (not even manually)