Citrix XenServer: failed to start Ubuntu VM after kernel upgrade

Recently I upgraded my Ubuntu VM to 12.04, which includes the new kernel. However the VM failed to reboot with following error:

Using  to parse /boot/grub/grub.cfg

To fix it,

1. boot your vm using the following command:

    xe-edit-bootloader -n your_vm_name -p 1

3. edit /grub/grub.cfg, comment out or remove the whole submenu section.

To avoid this, always remove the old kernels before rebooting. It automatically removes the submenu form grub.cfg. e.g.

aptitude remove linux-image-2.6.38-8-virtual

See also

• Ubuntu VM not starting on XenServer after kernel upgrade
• Ubuntu 11.04 boot failure after kernel upgrade because of submenu in grub.cfg