VirtualBox error “VT-x is disabled in the BIOS. (VERR_VMX_MSR_VMXON_DISABLED)”

After updating my Fedora 19 x64 I tried to open a VM I have installed on it but received this error:

VT-x is disabled in the BIOS. (VERR_VMX_MSR_VMXON_DISABLED)

It is supposed that I had to enable some VT-x configuration in the BIOS, but I’ve never touch the configuration before or after the update, so that couldn’t be the problem.
The current VirtualBox version installed is 4.3.4 and kernel is 3.11.10.

If you are in the same situation as me (you can’t change or you don’t want to change the BIOS config), what you can do is touch the VM. First, get the name and UUID of the VM you want to fix:

VBoxManage list vms
"My Guest VM Name" {e6b08efd-0453-497b-b934-ff8ad17baad3}

This gives you the VM’s name and UUID. Then turn off the long mode flag:

VBoxManage modifyvm "My Guest VM Name" --longmode off

Tha bad side of this is that I don’t know why it got broken after the update, the good thing is that I can continue working.


14 thoughts on “VirtualBox error “VT-x is disabled in the BIOS. (VERR_VMX_MSR_VMXON_DISABLED)”

  1. Jacob Dall December 12, 2013 / 1:01 pm

    Nice posting, helped me solve my issue, despite a few typos:
    – use ‘VBoxManage list vms’ instead of ‘VBoxManage list vm’
    – use ‘VBoxManage modifyvm “My Guest VM Name” –longmode off’ instead of ‘VBoxManage “My Guest VM Name” –longmode off’

  2. Joe December 17, 2013 / 3:51 pm

    Thanks for the post. Helped me resolve my issue as well.

  3. Venkat Ch January 2, 2014 / 6:01 am

    I’m getting the same error message, please let me know how to fix, if possible with couple screenshots and navigations wil be helpful…Thanks in anticipation please…

      • Venkat Ch January 2, 2014 / 2:49 pm

        Thanks for your quick response, appreciate it, as I’m not technical, I agree you have resolved the issues, get a chance can you please let me know how to resolve with step by step instructions and where and how to change the above mentioned parameters…

      • Eduardo Yáñez Parareda January 2, 2014 / 3:32 pm

        Step 1: open a terminal.
        Step 2: Type VBoxManage list vms
        Step 2.1: Copy the name of your VM.
        Step 3: VBoxManage modifyvm “Type here the name of the VM you copied on the previous step” –longmode off

      • Venkat Ch January 2, 2014 / 5:36 pm

        Thanks for your quick response Eduardo, appreciate it!

        As I have mentioned that I’m not technical, please excuse me for my dumb questions!

        1.Open terminal – means open a terminal by entering the ‘cmd’ command?
        2.Where I need to type VBOXManage list vms? Can I type any where (or) any specific path?
        3. Copy the name of your VM – how to find it?

        if possible can you please forward me the screenprints/screenshots. I know it’s an extra step, but will be helpful for a non-technical person. If possible please forward the screenprints documents to my email id :

        Thanks in anticipation and appreciate your time and help!

  4. Eduardo Yáñez Parareda January 2, 2014 / 6:17 pm

    I’m sorry, as you read in the post, this solution is for Linux, not Windows. I can’t help you if you’re a Windos user. Also I’m not a support guy, I’m only trying to spread my own experiences. Try to do it on a Windows terminal with ‘cmd’, but I’m not sure that the rest of commands will work there.


  5. Mark January 3, 2014 / 3:51 pm

    Just to add my observations, I too have this same “VT-x is disabled in the BIOS” error with virtual box version 4.3.6 r91406 running a 64 bit MS Vista guest on Ubuntu gnome 13.10 64bit (mainline kernel generic).
    In my case the issue only arises after suspending the host machine. Checking the bios shows that VT-x is enabled.
    I discovered by accident that shutting down the host and then disconnecting the power until the lights on the motherboard go out, resolves the issue until the host is suspended again.
    shutting down the host normally neither appears to provoke or cure the issue.
    Like I say, just observations……

  6. Bruno Menezes May 8, 2014 / 10:39 pm

    Thx man

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s