VirtualBox 7.0.20 not working on Ubuntu 25.04

[joakim-wallden]

My VirtualBox 7.0.20 doesn’t work on Ubuntu 25.04 (upgraded from 24.10, where VBox worked):

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).

[rubi1200]

Hello,

I moved your post to its own topic.

Please don’t hijack other threads with support requests that are not related to the original post.

Thanks.

[thingizkhan]

VirtualBox refuses to start when the KVM hyper-visor is already loaded
because Intel/AMD CPUs can only be in one “VMX/S-V” root mode at a
time.
During the 24.10 → 25.04 upgrade the kernel began loading KVM by
default, so the first hyper-visor in (KVM) wins and VirtualBox bails out
with VERR_VMX_IN_VMX_ROOT_MODE.

You have two options:

---

1 Run VirtualBox and stop using KVM

Unload the KVM modules once:

sudo modprobe -r kvm_intel kvm_amd kvm   # whichever unloads cleanly

then keep them from coming back:

echo "blacklist kvm_intel" | sudo tee /etc/modprobe.d/blacklist-kvm.conf
echo "blacklist kvm_amd"   | sudo tee -a /etc/modprobe.d/blacklist-kvm.conf

Reboot → lsmod | grep kvm should show nothing and VirtualBox will
start normally.

(Reverse the change any time by deleting the file in
/etc/modprobe.d/.)

---

2- Stay with KVM / QEMU and remove VirtualBox

KVM is now Ubuntu’s preferred hyper-visor (virt-manager,
Quick-emu/Quickgui, multipass, lxd --vm … all use it).
If you are happy to migrate the old VMs you can uninstall VirtualBox:

sudo apt purge virtualbox-7.0

and import the disks into a KVM front-end (virt-manager,
Quickgui, Boxes, etc.).

---

If you stick with VirtualBox

Make sure the matching modules are installed/loaded:

sudo apt install virtualbox virtualbox-dkms
sudo systemctl restart vboxdrv

Verify Secure Boot is off or the vboxdrv module is
MOK-enrolled; otherwise the kernel will refuse to load it.

Once KVM is black-listed (or removed) VirtualBox 7.0.20 works fine on
Ubuntu 25.04.

[joakim-wallden]

Thank you for the reply.

I am willing to switch to Boxes, but I need to be able to tell it where to create the disk image (not on the small system drive).