Update: Problem found. In BIOS DISABLE Limit CPUID MaxVal – Set Limit CPUID MaxVal to 3. Should be Disabled for Win XP. I had enabled this when I enabled VT-X support. VirtualBox works fine now. I have updated to Vbox 4.0.8 by installing from their PPA, but VirtualBox 4.0.4 OSE from Ubuntu PPA probably works just fine too. Both Ubuntu x86 and x64 guests work fine on Ubuntu x64 host.

Host: Ubuntu 11.04 x64 – VirtualBox-OSE 4.04 r70112 installed via package manager.

Guest: Ubuntu 11.04- but I never get that far.

Processor: Intel Core 2 Quad Q8400. with VT-X extensions. Enabled in BIOS.

• How can the problem be found?
• What can be tried to get this going?

Thanks,

ww

Guest is as follows: Guest_Ubuntu_32bit_Config