Installing the guest additions directly from the package provided by Oracle works:
wget http://download.virtualbox.org/virtualbox/4.0.6/virtualbox-4.0_4.0.6-71344~Ubuntu~natty_amd64.deb dpkg -x virtualbox-4.0_4.0.6-71344~Ubuntu~natty_amd64.deb your_directory_name mkdir iso_image sudo mount -l loop your_directory_name/usr/share/virtualbox/VBoxGuestAdditions.iso iso_image cd iso_image sudo ./VBoxLinuxAdditions.run It seems that there is an update from 4.0.4 to 4.0.6 which has not been shipped for the Windows version of VirtualBox. Maybe this update could be included in the backports (?). -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/773038 Title: X server error after installation of guest additions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs