How To Fix CentOS 6.4 Boot Hang After Upgrade

The Community Enterprise Operating System, commonly known as CentOS is a solid Linux Operating system similar to Red Hat Linux. We recently ran into a GUI boot problem after upgrading to CentOS 6.4 in a VirtualBox environment. Upon restarting after the upgrade, we noticed that during the boot process, the system showed either a blank screen or the CentOS progress bar for an extended period, almost one hour.

Apparently, the CentOS 6.4 upgrade broke X11 (the UNIX/Linux Graphical User Interface  or GUI). A few attempts at repairing the boot loader using the CentOS 6.4 installation disc did not help.

It turns out that removing the xorg.conf file takes care of the delayed or boot hang problem.

Here is the simplest way to get this resolved:

  • Restart the system and when you see the “Press any key to enter the menu” message, press any key. The list of available kernels will be presented and normally the latest kernel will be the first:
    CentOS 6.4 - grub_kernel_list
  • Press “e” to edit commands before booting.
  • Highlight the list item with vmlinuz in it by using the arrow keys and press “e”.CentOS 6.4 - grub_vmliuz
  • Now type “single” at the end of the line: CentOS 6.4 - grub_single_user
  • Press enter to be taken back to the kernel list, then press “b” to boot the system into single user mode. This will present you with a bash prompt:CentOS 6.4 - grub_bash
  • To rename the xorg.conf file, change to the X11 directory and type “ls” to see the contents:CentOS 6.4 - x11_dir
  • Rename the “xorg.conf” file –  “mv xorg.conf xorg.conf.bak”:CentOS 6.4 - xorg_conf
  •  Reboot the system by typing “reboot”

The system should now be able to boot into the GUI environment. Upon reboot, the system will create a new xorg.conf file with the correct settings.

As a side note, you can also easily rename the xorg.conf file by using a live CD like Knoppix to boot into the system, navigating to the X11 directory on the local disk and renaming the file.

If you experience this problem in a VirtualBox environment, you can re-install the VirtualBox Guest Additions tool by clicking on the “Devices” menu item and selecting “Install Guest Additions”.