ERROR: VT-X is not avaiable

[archbiri]

Hi I have an error (attachment) when I try to star VirtualBox last version on Leopard 1.5.6.
Someone can help me? THX

[Frank Mehnert]

Note that, starting with version 2.2.2, VirtualBox enables VT-x/AMD-V for new VMs by default. Actually it checks if these extensions are available. In your case it seems that the check was successful but VT-x is not available for any unknown reason. You should disable VT-x in your VM settings and should be able to start the VM again. However, without VT-x you will not be able to start 64-bit guests. It might also help to upgrade your BIOS if that is possible on a Mac.

[d0rk]

Note that, starting with version 2.2.2, VirtualBox enables VT-x/AMD-V for new VMs by default. Actually it checks if these extensions are available. In your case it seems that the check was successful but VT-x is not available for any unknown reason. You should disable VT-x in your VM settings and should be able to start the VM again. However, without VT-x you will not be able to start 64-bit guests. It might also help to upgrade your BIOS if that is possible on a Mac.

Hello. I am getting the same error as the OP when trying to run Ubuntu 9.04 on VirtualBox 2.2.2. When I go into the settings for the virtual machine, Enable VT-x/AMD-V is checked but grayed out, so I cannot uncheck it.

This is my first time using virtual machines so I am unfamiliar with what VT-x is and why the setting is unchangeable for me. If it helps I am running everything on a hackintosh Dell netbook with an Atom processor.

[Perryg]

If it is grayed out then VirtualBox sees that you do not have 64 bit capabilities.
You need to turn this on in your BIOS. If you do not have it then you can not run a 64 bit OS.
Download the 32 bit version of the OS you are trying to install if your bios does not support VTx/AMD-v

[d0rk]

Hmm, okay. I'm pretty sure the Atom can't run as 64-bit, but I will double-check the BIOS for any fancy settings. And I have verified that I am using an ISO with the 32-bit version of Ubuntu 9.04

[wardcomm]

Could some one on the development team please submit a ticket to have vt-x enabled but set to false on newly created systems. I was trully enjoying my experience with virtualbox until that change was made. I to have a processor that can use virtualbox but not when vt-x checked marked and then greyed out. There also need to be a way to import your old xml files into the GUI. I dont have it in my bios. so I can not turn off or on.

[sigmatelco]

Try to disable vt extension in advanced configuration of your vm.

For me it worked well.

Max

[davidfstr]

In VirtualBox 3.0.2, this option no longer appears in the Advanced pane. Nevertheless I managed to find a workaround to deselect the option despite it no longer appearing in the UI:

Under the ~/Library/VirtualBox/Machines directory you will find a folder for each virtual machine you have created. Within this directly you will find an XML file with the machine settings.

It looks like:

<?xml ...
<VirtualBox ...
  <Machine ...
    <CPU count="1">
      <HardwareVirtEx enabled="true"/>
      ...

Just change the 'enabled="true"' part to 'enabled="false"'.

Enjoy.

[Frank Mehnert]

The option moved to the System / Acceleration tab.

[PiddlyD]

This seems to be a problem with "Hackintosh" systems running OS X leopard on Atom processors. The developers don't seem to be able to get their minds around that - because I see a trouble ticket explaining the problem and being clear that this is the system configuration, and the developer is trying to claim that even though it shows VT-X enabled and grayed out so it can't BE disabled, it isn't "actually" enabled. Confirmed on a Lenovo S10 running OS X with VirtualBox 3.0.4.

In either case, Davidfstr has provided a work around that resolves the issue. The path David wrote out may be difficult for a Mac noob to understand.

In your "user folder", there will be a Library folder. Inside that library folder is a folder called VirtualBox, which in turn has a Machines folder. The XML file you find in there will have the line <hardwareVirtEx enabled="true"/>

(Your "user folder" is the folder that is named the same as your login, for lack of a screenshot for those who need pictures).

Change that to "false" and exit and restart Virtual Box (or open it if you had it closed) and the hardware virtualization extensions will be disabled.

Seems like a clear bug with VirtualBox, being that the setting is grayed out in the GUI but you can change it in the XML config file and that fixes the problem.

[DonGus]

The suggested solution (editing the .xml file) works fine for me. I'm just writing to inform that the problem exists also on my Dell Inspiron 1318, running Leopard 10.5.8 with vanilla Kernel (iAtkos 10.5.7 upgraded via apple software update to 10.5.. My CPU is a Core 2 Duo 6400, just in case.
Anyway, editing the .xml file works. Thanks! Wonderful app this VirtualBox! I was using VMWare Fusion, but now I think I'm gonna migrate to this, to avoid licensing costs.

[gmontag]

As noted by others, the xml fix works, I just wanted to add that you have to restart VirtualBox (the client, not just the guest OS) to get it to recognize the change.

A suggestion - attempt to auto-detect the VX feature but allow the end user to uncheck the box in future releases

[danbowker]

(I'm hosted on Windows 7 - not Mac, but thought this might help someone else)

I found that the settings for memory and video were way out of whack.
I had exported then reimported a virtual machine and the reimported version wouldn't start with the vt-x error stated above. I fixed the memory settings and all is good.

[smurfcorpse]

Some MACs had issues causing the computer to disable VT-X. I found this at Parallels forum.
http://forum.parallels.com/thread3273.html

Some suggest to put the MAC to sleep after it's done booting and wait a few seconds and then wake it up. You'll have to do this every time you boot.

[ejkitchen]

I am running Windows 7, 64bit. Today I decided to try Google Chrome OS and downloaded this product to run the image prepared by 3rd party site. Got to the point where I was ready to run and encountered this error. Found the XML file and made the edit as per a previous post and everything works like a charm. BTW, I also have VMWare and didn't know it could run this image. So I tried it and it ran without any issues whatsoever. After a bit of digging, figured out that VMWare Workstation was on auto for hardware acceleration detection and after failing to enabling hardware VT, it simply went to software emulation.

Now, before you tell me to go into my BIOS and enable hardware VT, I cannot. I have an Asus Z7S WS with BIOS 401 and it has a known bug where hardware VT does not work under 64bit Windows (or so ASUS says and apparently there is a new BIOS fix coming out that will solve this issue. I am not sure it would work under 32 bits as well but the ASUS guy said it would but somehow I don't believe him). In any case the way VirtualBox tests for hardware VT is broken. It probably does a quick test to see if my CPU has the feature but does not try to enable it to see if can enable it and use it. Here is one example of hardware VT being there but not working and a user not being able to do anything about it. I am sure there are other similar scenarios that have not been thought of with similar issues. So the developers should offer a way to 'uncheck' hardware VT if it is checked and I would also add another mode called automatic where the system tries what it thinks is there and if it fails, revert to software emulation and notify the user.

EJK