virtualbox.org

Hello Community,

when I try to start a VM, following error occurs:

VT-x is not available (VERR_VMX_NO_VMX).

Fehlercode:E_FAIL (0x80004005)
Komponente:ConsoleWrap
Interface:IConsole {872da645-4a9b-1727-bee2-5585105b9eed}


Hyper-V is disabled on my machine: In BIOS VT-x options are enabled.

OS: Win 10.0.14393
VB: 5.1.2 r108956

On the start page, only Hyper-V is displayed as HW Support: Any ideas?

Thx

In another thread a user reported that he had to switch off VT-x in BIOS, start Windows, go back to BIOS and reenable VT-x to get it back working.

Martin wrote:Switch off VT-x in BIOS, start Windows, go back to BIOS and reenable VT-x

Thx Martin for the hint. I've already tried this before. Didn't fix my issue.

You have to power off your PC (not hibernate) and then restart, in order for the CPU to start working in the new mode.

See this related topic: FAQ: I have a 64bit host, but can't install 64bit guests.

Tried this, but unfortunately it didn't resolve my issue.

Checked CPU state: Virtualization is enabled: I can't explain the Hyper-V reference in the VM Settings pane.
Are there any further ideas?

If it didn't resolve your issue then you didn't read it thoroughly enough. The FAQ lists all reasons why VT-x/AMD-v might not be available, and gives you a checklist to go through.

OK, checked 1) and 2) carefully.
Removed battery, restarted several times with different options, flashed BIOS etc.

How can I find out, whether another host application already uses VT-x?

Please post a VM log file. With the VM fully shut down, right click and "Show Log" in the GUI, save "VBox.log" (ONLY) to a zip, and attach the zip here.

Please see attached file: Thank you for your effort!

Unfortunately the log aborts before giving me the information I wanted.

Please tell me your exact CPU model as reported by "This PC".

Intel(R) Core(TM) i7-3740QM CPU @ 2.70GHz, 2701 Mhz, 4 Core(s), 8 Logical Processor(s)

CPU is definitely VT-x ready. With another Installation, 64bit VMs worked on this machine.

Yes, the CPU supports VT-x. Do you have any third party antivirus installed? If so, have you tried disabling it?

AV is Windows Defender. Deactivated Real-Time-Protection, but this didn't resolve the issue.
In another post, a possible cause is the activation of nested virtualization for Windows 10. I will try to find out how to check/disable the feature.

LexionTT wrote:In another post, a possible cause is the activation of nested virtualization for Windows 10. I will try to find out how to check/disable the feature.

That only applies if Hyper-v is enabled, otherwise there is nothing to nest within. Also, the symptoms seem to be that VirtualBox thinks VT-x is available, but then crashes. That is not your symptoms.

Just joined to post an answer, as I've been struggling with this too. It seems that after the RS1 update the Device Guard / Credential Guard is grabbing the VT-x process. This link: https://technet.microsoft.com/en-us/itp ... tial-guard has a section on removing it from your computer. It wasn't clear to me if it was either the group policy, registry, and bcdedit changes and/or the PowerShell script that were needed - so I did both with a final restart afterwards. Hope this helps.