Updating Ubuntu major version in a Virtual Box VM

Yesterday I upgraded from Ubuntu 8.10 to 9.04 using the system’s Update Manager (System>Administration>Update Manager). This worked perfectly, which is impressive considering I upgraded to a new major version of the software, but because the Ubuntu in question is a VirtualBox VM the new OS version’s X11 video software wouldn’t work properly. It complained that it couldn’t find a suitable driver and it would not work in low resolution mode.

The fix was to log in to the console (a dialog box reporting the error offers you this option), then mount the VirtualBox kernel additions ISO image (which is called VBoxGuestAdditions.iso and is, I think, something internal to VirtualBox and hence always associated with the VM by default). The ISO image contains scripts called VBoxLinuxAdditions-<arch>.run [the one suitable for my hardware is VBoxLinuxAdditions-x86.run], which you can run to install the twiddly bits, hacks, patches, extensions or whatever that enable video and probably a lot more too.

$ mount /media/cdrom
$ cd /media/cdrom
$ sudo ./VBoxLinuxAdditions-x86.run
[script runs]
$ sudo shutdown -r now