Ubuntu 12.04 64bits on a Windows 7 host install error

[Umo]

VBoxManage modifyvm <vmname> --longmode on

I am having a problem installing UBUNTU 12.04, 64 bit, in a VB v4.3.2, with error message:

" Unable to boot. This kernel requires an x86-64 CPU, but only detected an i686 CPU...."

I am running VBOX 4.3.2, r90405, on 64bit Windows 7 Pro on a machine with an ASUS Z87-K mainboard with an i7-4770K processor. VT-x is - according to the BIOS - enabled (there is no option to turn it on or off).
The Install in VB does not show 64 bits as an option, only Ubuntu, but I have run the VBoxManage command

VBoxManage modifyvm <vmname> --longmode on

and the little icon to the left of the virtual machine in VB shows a '64' in the upper left corner, over a '2.6'.
One more info: Ubuntu can be directly installed on this machine as a secondary system without any problem. So, there is nothing wrong with Ubuntu. but I need it in a VM.

What to do???

Umo

Posts: 1
Joined: 17. Nov 2013, 11:51

[mpack]

Did you choose a 64bit template for the VM? Is VT-x enabled in the VM settings?

Anyway, please post a VM log file. See Minimum information needed for assistance.

[Umo]

Did you choose a 64bit template for the VM? Is VT-x enabled in the VM settings?

Anyway, please post a VM log file. See Minimum information needed for assistance.

There was no choice of a 64bit template for the VM; the little icon to the left of the UBUNTU machine just says 'Ubuntu'. There is also no way to set VT-x enabled in the VM settings. where should that be?

Anyway, attached is the log. In line 478 it says:
HMR3Init: Falling back to raw-mode: VT-x is disabled in the BIOS.
BUT: the BIOS says: VT-x enabled !

Umo

[Perryg]

Make sure hyper-v or xp mode is disabled.

[Umo]

Where do I do that?

[JacquesLeRoux]

I had exactly the same problem with exactly the same configuration, but a slightly newer VirtualBox version.

To be more clear:

• ASUS Z87-K mainboard

• i7-4770K processor

• VT-x enabled in BIOS

• Windows 7 Pro 64 bits

• VBOX 4.3.4, r91027

• ubuntu-13.10-desktop-amd64.iso

• Error message: " Unable to boot. This kernel requires an x86-64 CPU, but only detected an i686 CPU...."

I felt very stupid when I found this trick (I can't post the link due to "You must be a member for 1 days and have 1 posts before you can post urls.")
<<When you define a new VM, you must check the "Ubuntu 64bits" option under the Version drop-down menu.>>

I did not check below in the dropdown list. There is indeed a Ubuntu64 option, did you check?

All went well then

HTH

Jacques