VirtualBox can’t operate in VMX root mode

You might see this VirtualBox error when trying to start a virtual machine or create a new one.

VirtualBox can’t operate in VMX root mode. Please disable the KVM kernel extension, recompile your kernel and reboot.
VBox status code: -4011 (VERR_VMX_IN_VMX_ROOT_MODE).

Result Code:
IConsole {d5a1cbda-f5d7-4824-9afe-d640c94c7dcf}

But it’s an easy fix.

$ modprobe -l | grep kvm

Remove the modules.

$ sudo modprobe-r kvm-amd
$ sudo modprobe-r kvm-intel
$ sudo modprobe-r kvm

Remove them in that same order or else you’ll get this error:
FATAL: Module kvm is in use.

VirtualBox Black Logo BoxThe modules will reload when you reboot and you’ll probably forget about this little problem… try to run a VM… Virtualbox will complain, and then you’ll have to remove the modules all over again.

You could blacklist the modules so they don’t load automatically, or stop using the generic distribution kernel and compile your own, or go back to a pre 2.6.20 kernel since KVM was first added to 2.6.20 in February 2007. But more of a pain than it’s worth for a generic desktop system running a Fedora, Ubuntu, Debian, Arch, etc. distribution.

$ cd /etc/modprobe.d/
$ echo “kvm-amd” >> ./blacklist.conf
$ echo “kvm-intel” >> ./blacklist.conf
$ echo “kvm” >> ./blacklist.conf