Install VirtualBox’s guest additions are relativly stright forward in Ubuntu. But for Kubuntu 10.04 it’s takes a little more work.

Open the terminal and execute the following commands. First, check to make sure the system is up to date.

sudo apt-get update
sudo apt-get upgrade

Restart the system after these have been installed. Next we need to install and get a few things.

sudo apt-get install dkms
sudo apt-get install build-essential

Restart the system again.
Now we can install the guest additions. Devices -> Install Guest Additions… Virtual CD should mount automatically.

cd /media/VBoxLinuxAdditions_x
sudo ./

Install might take a little while to compile. After it has completed, restart the system. Guest additions have now been successfully installed.