Update to VBOX 5.2.18-124319 Crashed all my vm's

[Froto]

Hello - I am running a fully patched Win 10 64bit OS. Hyper-V is no enabled or used. Bios is set correctly. All settings are in place. Updated to VBOX 5.2.18-124319, and none of my VM's will run now. All have the error message:

Failed to open a session for the virtual machine Kali-Linux-2018.2-vbox-amd64.

VT-x is not available (VERR_VMX_NO_VMX).

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

I have researched the error, and nothing works. I have reinstalled all items, checked and unchecked. Please advise...
UPDATE: I did try to RESTORE to a prior version of Win 10 in case there was something in the update that affected Hyper-V relationship with VBOX. No luck...getting frustrated...almost to a point where I would use Hyper-V...

[socratis]

Please read really carefully the following FAQ: Diagnosing VirtualBox Hardening Issues for some generic guidelines/ideas. Remember, these are guidelines, not the exact solution, you have to use your judgement as to which program might be responsible...

After making 110% sure that Hyper-V is disabled in the Windows Features, you might want to make sure that Fast Boot is disabled and do a cold boot (i.e. shut down the host for a minute or two). You also must make sure that nothing else is using Hyper-V, things like antivirus, debuggers, emulators, etc.

Here's a rather big laundry list of things to try: https://www.virtualbox.org/ticket/17741#comment:9 and viewtopic.php?f=6&t=75274&p=421946#p421946

And finally, read the Microsoft article on Credential Guard: Manage Windows Defender Credential Guard.

Yes, it's not easy to tell who might be using Hyper-V. I (we all) wish it was...

getting frustrated...almost to a point where I would use Hyper-V...

Nobody here can (or will try to) prevent you from doing that, so I'm not even sure why you're bringing it up...