Audio Processing Object won't load on Windows 7, even though it's WHQL certified/signed RRS feed

  • Question

  • Hello all

    I am developing a Windows Audio Processing Object (APO) to run with the inbox USB driver for my USB Headphone.  I am having problems with Windows 7 which I believe have to do with my driver package files signing, but my efforts so far have not solved the issue - please help!

    Here's the Issue History:

    *  My APO worked fine on Windows 10 but not on Windows 7.  When I set DisableProtectedAudioDG registry key = 1, my APO loaded on Win 7 no problem, so my issue seemed clearly associated with the Protected Environemnt (PE) enforced by Win 7...

    *  I got my customer to register for WHQL and get the driver package files signed and tried again - APO still wouldn't load under Win 7

    *  I added required directives to my .inf:

     - re-submitted to WHQL and tried WHQL-signed again - APO still would not load under Win 7

    *  I realised that I should regenerate my .cat file because I had changed the .inf, so I did, resubmitted to WHQL and tried WHQL-signed package files again - APO still would not load under Win 7

    *  I had a look at the logs for the scenario where my APO would/should load and run and I noticed errors for each of my package files of the form:
    Drp specified for non NT5 Crypto file 'C:\Windows\system32\MY_LIBRARY.dll'.
    !!!  cpy:   Error 186: The flag passed is not correct.
    *  I verified with SignTool that my modules are correctly signed, including page hashes and timestamps - all looks ok.

    So that's where I'm at and I'm a little lost and unsure what/how to investigate from here.


    My few thoughts:
    *  I understand my customer should have signed certain legal agreements with Microsoft in order for the WHQL qualification to assign the necessary PETrust Attributes to the WHQL digital signature, but I am unfortunately not in a position to verify whether they have correctly executed this.  Is there any tool/technique that I can use to doible-check that the signatures include all the Attributes that Windows 7 needs to see?

    *  Are there any other debug/log tools/techniques that I may use to look at how Windows Audio Engine sees my APO and why it won't load it?

    *  Does anything stand out for you experts out there in terms of likely/simple/stupid mistakes/assumptions I've made?

    Thanks in advance
    Thursday, March 14, 2019 10:20 PM