3

I have just found out that VT-x is not working anymore on my Windows 10 host in VirtualBox 5.0.14.

Trying to boot one of my x64 guests now causes a "VT-x is disabled in the BIOS for both all CPU modes" error and I can't select more than one CPU or create x64 guests anymore.

VT-x is enabled in the BIOS and Hyper-V is not installed. In fact, VT-x worked just fine until today.

I have tried rebooting several times and reinstalling VirtualBox, but to no avail.

No one seems to have had a similar issue.

What could it be?

The host is a Lenovo Yoga Thinkpad 15 running on an Intel i5-5200U @ 2.20 GHz.

7
  • Do you have some information about the hardware of the host?
    – doenoe
    Feb 16, 2016 at 12:05
  • See the question. Feb 16, 2016 at 12:09
  • I have just found out that VT-x is not working anymore on my Windows 10 host in VirtualBox 5.0.14.. What did you change before it stopped working?
    – doenoe
    Feb 16, 2016 at 12:16
  • I didn't change anything, that's the weird thing. I rebooted my PC and it just didn't work anymore. I remember it finished installing updates during the reboot, but looking at the updates it doesn't seem like virtualization was involved. Feb 16, 2016 at 12:30
  • What updates did you install? Try to revert them and try to start the VMs once again
    – doenoe
    Feb 16, 2016 at 12:43

2 Answers 2

0

I encountered the same problem and solved it: Something was using the VT-x features, and according to a post on oracles forum (lost link, google a bit) vbox uses virtualisation in way not compatible with the former. You can confirm if this is the case by running msinfo32.exe, scrolling to the bottom and look for a string that goes like "A hypervisor was detected..." as the very last line. If you see ~4 lines about hyper-v capabilities, your problem is different than mine, and the solution might not apply.

So now goes a potentially frustrating search for what is using virtualisation...

If hyper-v is installed and running (check in windows services) you can try and remove it; Control panel > programs > Turn Windows features on or off

People have also mentioned "other anti virus than BitDefender" and things running in XP compatibility mode as being the culprit. I tried killing all processes and stopping all services - no luck (do this at your own risk, you might break something...)

Finally I was hinted to a new feature called "Virtualisation Based Security" in windows. Go to taskmanager and look under "details" tab for a process called Secure System. If this runs, you've likely found the reason for your trouble; Despite removing hyper-v as described above, this feature runs some hypervisor way down deep, blocking virtualbox.

In regedit.exe set HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\DeviceGuard to 0 and reboot. Did the trick for me. Beware that you're disabling a security feature, see https://technet.microsoft.com/en-us/itpro/windows/keep-secure/deploy-device-guard-enable-virtualization-based-security for details.

0

Today I had the very same problem. After installing Docker for windows on Windows 10. Apparently 'Docker for Windows' and VirtualBox cannot be installed together on the same machine. The reason for that is 'Docker for Windows' is based on Hyper-v. This is well documented and explained here.

So we have to chose Hyper-v or VirtualBox, can't have both installed. In my case I uninstalled 'Docker for Windows' and removed Hyper-v from my machine. Instructions to remove Hyper-v are here. Than VirtualBox worked again.

As for using Docker containers, I can still run Linux Docker containers on VirtualBox Linux guests without Hyper-v (actually that is exactly the Hyper-v Linux implementation).

1
  • You might consider adding further quoted reference from the content of the links you provided in case the links ever go bad, the content will still be on the answer. Oct 21, 2017 at 22:41

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .