Ubuntu – Cannot install Ubuntu in VirtualBox due to “this kernel requires an x86-64 CPU, but only detects an i686 CPU, unable to boot” error

virtualbox

I was trying to install Ubuntu 12.04 in VirtualBox 4.2.12r84980. I see 

this kernel requires an x86-64 CPU, but only detects an i686 CPU, unable to boot

But I am using a 64 bit Windows 8, and trying same .iso for trying Ubuntu. Then what is the problem?

Best Answer

To be able to run a 64-bit OS in Virtual Box we have to make sure the virtual machine's architecture is set to 64-bit too.

  • Choose Ubuntu 64-bit in General -> Basic settings on creation of your VM

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  • In addition, for running 64-bit guests it is recommended to enable the Input/Output APIC in the System -> Motherboard settings for your virtual machine:

  • In the System -> Acceleration tab we may want to enable the hardware virtualization features VT-x/AMD-V of your CPU.

  • On the host system we may have to enable hardware virtualization in the BIOS.

  • In some systems a host BIOS option to prevent non-trusted execution needs to be turned off (source).

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