How to run Windows under VirtualBox on Fedora Core

Recently I needed to install Windows XP under VirtualBox on my Fedora Core 9 mashine.

After a successfull VirtualBox installation, I got an error when trying to install Windows from .iso image:

VirtualBox can’t operate in VMX root mode. Please disable the KVM kernel extension, recompile your kernel and reboot (VERR_VMX_IN_VMX_ROOT_MODE).

The error message means your kernel has loaded kvm module which conflicts with VirtualBox.

How to fix the problem?

The first of all, become the super user.

To ensure the module is loaded execute this command in console:

#modprobe -r kvm


FATAL: Module kvm is in use.

Then execute this:

#lsmod | grep kvm


kvm_intel              41144  0
kvm                   115008  1 kvm_intel

Note: You may see ‘kvm_amd’ instead of ‘kvm_intel’.

This means the kvm module is loaded.

To unload the module execute the following:

#rmmod kvm_intel

and then

#rmmod kvm

(sequence of the commands does matter)

If all is ok no extra output will be present.
Note: You should execute

#rmmod kvm_amd

in case you’ve seen ‘kvm_amd’ on previous steps.

The kvm module is unloaded and now you can try to install Windows under your VirtualBox without “VirtualBox can’t operate…” message. However you may want to prevent the kvm module use on next system startups:

In /etc/modprobe.d/ create file named ‘nokvm’ (or with any other name you like) and put into it the only line:

install kvm /bin/true

Congrats, you’re done. Now you can reboot your mashine and enjoy using VirtualBox :)

I believe the described will work for Fedora Core 8 either.

More explanation about described you can find here:

This entry was posted on Thursday, February 26th, 2009 at 17:48 and is filed under linux. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

5 Responses to “How to run Windows under VirtualBox on Fedora Core”


thank for that hint it works perfect.
is used it with following releases:
Fedora 11: Linux #1 SMP Fri Sep 25 04:43:32 EDT 2009 x86_64 x86_64 x86_64 GNU/Linux
VirtualBox: VirtualBox-3.0.4_50677_fedora11-1.x86_64

greetings from austria

Thanks for the tip.

It works fine for me on Fedora 12.

Hi — works for Fedora 12 x64 as well. Warning message: nokvm needs to be renamed nokvm.conf or it will (someday) be ignored.

I’m running F12x64 on a quad-proc system (smb/rsync/www), and installing WXPx32 under PuTTY/Xming. Tried KVM, expect it’ll get better in the future (esp. as a fallback from VB if Sun AKA Oracle “Sundowns” it. ;-) )

There’s now a VB yum repo:, see bottom of page

Also, typo on next to last line — “mashine”. Perfect description, I wish other authors would be as accurate and NON-verbose. Thanks!

i can’t unload the module kvm

rmmod kvm_intel
ERROR: Module kvm_intel is in use

I would advice for, they can beat most of the vps providers with their products and non stop support.

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