I am having a 64 bit laptop which does not support VT. It is a Dell Machine.For some recovery (I have a server whose rsync backup I am recovering) I necessarily need to have a 64 bit guest.The guest OS is CentOS. My host OS is Ubuntu 10.04 (with all updates) and guest to create is CentOS 64 bit 5.5 version.

How ever when I started the installation from ISO it stopped saying your CPU does not support long mode.Use a 32 bit distribution. I came to Virtualbox because similar error I had in using Vmware which I had posted in a thread here how to run a vmdk image on another 64 bit machine which does not have vt support the thread seems to have suppressed so posting this new one.

So I got a vmdk file (which was given to me by a kind friend) which had the 64 bit guest created on his hardware which supported VT so I tried to import the same in Virtualbox.Unfortunately I did not see any option which I can use to import the vmdk file to Virtual box (though there were options to import open virtual image formats) so I thought of creating a guest OS from scratch and tried creating the 64 bit guest on this system using Virtualbox. Virtualbox was downloaded from here http://download.virtualbox.org/virtualbox/4.0.2/virtualbox-4.0_4.0.2-69518~Ubuntu~lucid_amd64.deb and it installed successfully. But 1) To import the vmware file there was no option in Virtualbox 2) The creation of 64 bit guest on 64 bit hardware in above scenario had failed.

Is there a remedy for same.Thanks in advance.

2 Answers 2


I have a HP dv-6 laptop running Windows 7 Home Edition (64-bit). It has a quad core AMD Phenom processor and, I to cannot enable the VT feature in the BIOS (because it's not there) but, I've installed VMWare Server 2.0x and I'm able to run any Linux 64-bit guest. I made the move from Virtual Box 3x to VMWare Server 2x because I couldn't run 64-bit guests.


You can't run 64-bit guest using VirtualBox on hardware without VT. Seems silly that you can't run the same type as your host without VT, but you can't. Either use 32-bit guest or buy hardware that supports VT. You might also want to look into a para-virtualization solution like Xen which can run 64-bit without VT. Also VMWare may be able to emulate 64-bit.

One think you may want to check is whether your CPU actually supports VT and maybe just your BIOS doesn't enable it. There may be options to install a custom bios to enable VT support if you CPU actually supports it.

Here are details from Wikipedia. It appears that some AMD processors may support 64-bit software-only virtualization but Intel CPUs do not and I don't know if VirtualBox supports the features of those AMD CPUs.

  • 2
    Actually ALL AMD cpus from a certain model upward support hardware virtualization. It is only intel playing the game with different versions o fthe same processor supportin different features. I think everything post socket 939 on AMD supports Hardware virtualiaztion.
    – TomTom
    Jan 25, 2011 at 12:04
  • CPU Virtualization is only required for hypervisors, not paravirtualization or emulation. In particular emulators (like QEmu without KQEmu/KVM will emulate a 64-bit processor running on a variety of hardware).
    – Chris S
    Jan 25, 2011 at 13:23

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