virtualbox.org

Win 8 Ubuntu 12 "kernel requires an x86-64 CPU, but only detected an i686 CPU"

I have installed "VirtualBox 4.3 for Windows hosts x86/amd64." But when I attempt to install "ubuntu-12.04.3-desktop-amd64," either from CD/DVD or from ISO image, I get the following message.

"This kernel requires an x86-64 CPU, but only detected an i686 CPU. Unable to boot - please use a kernel appropriate for your CPU."

I am posting this on both, VirtualBox and Ubuntu forums. I know mobo and proc support hardware virtualization because I was able to run MS Hyper-V. However, there is nothing in the mobo BIOS that allows me to turn hardware virtualization on or off... it's just automatically on. Also, I have tried turning off the Hyper-V Service but that appeared to make no difference. So rebooted system and tried again. I have also tried completely uninstalling/reinstalling VirtualBox. Any and all suggestions welcome!

Motherboard: Gigabyte GA-F2A85X-UP4(rev. 1.0)
Chipset: AMD A85X
BIOS: AMI EFI version F4
Processor: AMD A8 6600K (Socket FM2) 64-bit Quad Core
Memory: 16 GB DDR3
Operating System: Windows 8, 64-bit

tobe1 wrote:Win 8 Ubuntu 12 "kernel requires an x86-64 CPU, but only detected an i686 CPU" ... I was able to run MS Hyper-V...

Disable Hyper-V in Windows. Also, read the manual on this topic.

socratis wrote:

tobe1 wrote:Win 8 Ubuntu 12 "kernel requires an x86-64 CPU, but only detected an i686 CPU" ... I was able to run MS Hyper-V...

Disable Hyper-V in Windows. Also, read the manual on this topic.

Thanks, socratis. oh, and I did read the manual, twice. I saw no mention of my issue, which is why i came to the forums for help. The manual does state, "Warning
Do not run other hypervisors (open-source or commercial virtualization products) together with VirtualBox! While several hypervisors can normally be installed in parallel, do not attempt to run several virtual machines from competing hypervisors at the same time. VirtualBox cannot track what another hypervisor is currently attempting to do on the same host, and especially if several products attempt to use hardware virtualization features such as VT-x, this can crash the entire host. Also, within VirtualBox, you can mix software and hardware virtualization when running multiple VMs. In certain cases a small performance penalty will be unavoidable when mixing VT-x and software virtualization VMs. We recommend not mixing virtualization modes if maximum performance and low overhead are essential. This does not apply to AMD-V."

I took this to mean that it is okay to have multiple hypervision apps simultaneously installed, but just don't run virtual machines in more than one app at at time. Additionally, the very last statement seems to imply that the entire warning only applies to Intel's VTx, and not AMD-V (which is what I have). So please forgive my naivete and seeming lack of research.

You and others reading this will be pleased to know that after diabling hyper-v (see note* below) and rebooting, I was able to easily install without issue (see note ** below).
*launched elevated command prompt (run as administrator) and entered the following script. "dism.exe /Online /Disable-Feature:Microsoft-Hyper-V" (without the quote marks, of course).
**when selecting OS type to install, I chose "Other/Other 64bit"

Thanks again!

I'm getting the same message on Windows 7 Enterprise 64-bit on a Lenovo T510 laptop. I've gone into Features and see nothing about hyper-v. I already enabled both "virtualization" and VT-d in the BIOS.

tobe1 wrote:This does not apply to AMD-V."

You see that's the thing... I'm not an expert on VBox, nor do I have several test machines to try things on. The only thing I suggested was something that was really common in the threads as a potential solution. Maybe the manual needs an update?

RodBarnes wrote:I'm getting the same message on Windows 7 Enterprise 64-bit on a Lenovo T510 laptop. I've gone into Features and see nothing about hyper-v. I already enabled both "virtualization" and VT-d in the BIOS.

And then I realized I had mistakenly selected the "Ubuntu" rather than the "Ubuntu 64-bit" vm type. DOH! So, be sure you select the correct vm type.

Even after I disabled Hiper-V, I still couldn't turn on the VM.
Then I found that the version of OS in VM setting was Ubuntu 32bit.
It is working well fter I corrected it to Ubuntu 64bit.
Hope someone could use of this tip.