Error:

Received the following error after installing Ubuntu 8.04 server on my Ubuntu 8.04 laptop via virtualbox:

Starting up …

This kernel requires the following features not present on the CPU:

0:6

Discussion:

According to a few sources this happens because because the OS kernel is assuming the Physical Address Extensions (PAE) are present without checking for them first.

Resolution:

To fix I did the following (Older VirtualBox Versions):

1. Shutdown the VM.
2. Open the settings on the VM through the Sun xVM VirtualBox manager
3. General -> Advanced -> check Enable PAE/NX
4. Start your VM

Newer Virtual Box Versions:

1. Shutdown the VM.
2. Open the settings on the VM.
3. System -> Processor -> check Enable PAE/NX

Alternatively, with Ubuntu, you should be running the virtual kernel. Install server as normal, then before rebooting hit alt-f2 to get a shell. Run “chroot /target”. Then “apt-get install linux-virtual”. You could also do the same by booting for the install CD and selecting the option to repair the install and running apt-get from there.Enjoy :)