Is it any way to connect VirtualKD 2.8 to VBox > 4.3.

I googled it but the nearest result was VBOX_WITH_VIRTUALKD config flag and some change logs about stub/loader.

OK, because of lack of information in my question, I try to explain my problem...

I start installing the VirtualKD from Ref I using VKD 2.8. exactly in step 2 it said

Unable to cast COM object of type 'VirtualBox.VirtualBoxClass' ...

So I start googleing and i found a great article Ref II. I compiled the C# code and ran it in the VirtualKD-2.8 directory. the first problem is gone but the virtual box said:

Unable to load R3 "C:\VirtualKD-2.8\VBoxKD64.dll": Not signed ... (VERR_LDRVI_NOT_SIGNED)

Again I start googleing... the problem is for VBox > 3.1, it force signed dll loading in windows. so I signed the DLL by a self generated sign ( and of curse I added it to my trust list ). now the virtualbox braks with

Unable to load R3 module "C:\VirtualKD-2.8\VBoxKD64.dll" None of 1 path(s) hav a trust anchor.: ... (VERR_CR_X509_CPV_NO_TRUSTED_PATHS).

so I used a globally trusted sign to do the job but I got a FATAL error from vbox...

1 Answer 1


As I think, someone else might have this problem, I have to answer my own question...

First. please read the question carefully ( it is long but worst it ). Then...

As Virtual Box only accepts signed DLLs so you have to sign the VBoxKD64.dll and/or VBoxKD.dll. it is not easy to find a trust sign so avast guys make a pre-signed virtual-kd available for download here

Now we have another problem. Virtual Box will not load DLLs that are not owned by NT SERVICE\TrustedInstaller so we have to add Virtual-KD directory to it's kingdom. ( read this if you have no ida about what I say )

Also it is a good description in the avast package named Install.txt.

  • The Avast link you provided doesn't have a signed copy of the driver in the .zip ?
    – Peanut
    Commented Aug 25, 2015 at 23:03
  • You are right. my problem was installing Virtual-KD on Virtual Box. It doesn't need Virtual-KD driver to be signed... some useful information about your problem is present at VKD forum.
    – diener_k
    Commented Sep 6, 2015 at 4:32

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.