Unable to run VM with Vbox 6.0.6 on windows 10 (1809)

[_BeepBeep]

Hello,
I just installed VirtualBox V6.0 (6.0.6r130049) on an Intel i7-4770 machine, with 32 GB RAM, running Windows 10 Version 10.0.17763.404.
This version of VirtualBox replaced on the same computer a VirtualBox 5.2 that worked properly.

My problem today is that any attempts to create a new virtual machine, or launch a VM that was well running on version 5.2 ends with an error with the following message:

Échec de l'ouverture de session pour la machine virtuelle Kali-Linux-2017.2-vbox-i386.

(VERR_NEM_MISSING_KERNEL_API).

VT-x is not available (VERR_VMX_NO_VMX).

Code d'erreur : E_FAIL (0x80004005)
Composant : ConsoleWrap
Interface : IConsole {872da645-4a9b-1727-bee2-5585105b9eed}

I immediately verified that the VT-x mode is active and that Hyper is disabled. I do not know what else to do.

Thanks for your help.

[mpack]

Disable Hyper-v on the host OS.

[_BeepBeep]

I already did it by unchecking Hyper-V in control panel, but perhaps there is something else to do?

[mpack]

Follow the recommendations in this topic: I have a 64bit host, but can't install 64bit guests.

[daveh42]

I have the same issue. I have updated to windows 10 (1809) twice before, but had to revert since none of my VMs would start. I have updated again to 1809 and also updated to VirtualBox 6.0.8 r130520 (Qt5.6.2). I have followed all of the steps in "I have a 64bit host, but can't install 64bit guests" regarding Hyper-V, CredentialGuard, and Core Isolation. I powered down my machine and restarted and I still cannot start any VMs.

Are there any other things to check?

[mpack]

There not much to add. If you get VERR_NEM_MISSING then you DO have Hyper-v enabled in some form. The list of things that imply Hyper-v varies almost daily, especially if you are on the rapid release Win10 schedule.

[daveh42]

Sorry, I misread the original post. I do not get any error message. The VM hangs on a black screen when starting.

[daveh42]

It turns out I had missed disabling Windows Defender Application Guard in Windows Features. Now, my VMs start.

Thanks for your help.