virtualbox.org

Hi,
On my Windows 8.1 I have installed 4.3.15 r95286 VirtualBox version.
On my virtual box I created a new WIndows 7 machine. It work fine until yesterday when I change the new antivirus (BitDefender Internet Security 2015).
Now when I try to start the machine I receive an error message:

Details:
Apertura di una sessione per la Macchina Virtuale win7 non riuscita.
VT-x is being used by another hypervisor. (VERR_VMX_IN_VMX_ROOT_MODE).
VirtualBox can't operate in VMX root mode. Please close all other virtualization programs. (VERR_VMX_IN_VMX_ROOT_MODE).
Codice 'uscita: E_FAIL (0x80004005)
Componente: Console
Interfaccia: IConsole {8ab7c520-2442-4b66-8d74-4ff1e195d2b6}

I don't have other virtualization programs !
I search on this forum and on the net but I didn't found any solution.
Can help me ?

Thanks

Believe what error messages tell you. Something else is using VT-x.

I would say: disable Hyper-V. If you are correct that you don't have it installed (it's present by default on Win8 Pro builds), then I'd look to see if BitDefender uses the feature.

Also: please don't discuss VirtualBox test builds outside of the discussion thread where you got it. I'm letting this go because the issue is not version specific.

I've same error with BT Antivirus 2015.

Disabling "active virus control" works fine (permissive option don't)

The exclusion process don't work too.

The BitDefender forum is most likely discussing an entirely different problem. See the discussion "4.3.14 conflicts with anti-virus" which is stickied near the top of the "Windows Hosts" forum.