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SmartSDR 2.8.1 and BSOD

Have started having BSOD computer reboot after SmartSDR 2.8.1 installation. Computer reboots with a portcls.sys error. This sometimes clears on the re-boot and sometimes not. Once I had to reboot three times in a row to get the system operational again.

This is tied to the DAX program opening.

I see this issue mentioned in the release notes on SSDR 2.8.1 as an issue after 2.6.1 Alpha testing.

Any resolution yet?





  • Mike-VA3MW
    Mike-VA3MW Administrator, FlexRadio Employee, Community Manager, Super Elmer, Moderator admin

    Hi Darryl

    I think I answered this on FaceBook, but if not, it is something that is seen by some customers and some do not see it at all. Not that that helps you at all.

    I've opened a support ticket for you.

  • Darryl
    Darryl Member ✭✭

    Hey, Mike,

    Thanks for the response here. I don't do Facebook, so would not have seen it there.

    Sounds like a problem that is going to be fun to troubleshoot.

    Thanks for opening the ticket and we'll see where it leads.




  • Mike-VA3MW
    Mike-VA3MW Administrator, FlexRadio Employee, Community Manager, Super Elmer, Moderator admin

    You won't like my answer, but I thought I would share it. It is like using a hammer to fix it. :)

    I had a couple of friends with this issue and I suggested they rebuild their Windows computer from scratch as they were not able to isolate it. They did and the problem went away.

  • Rich M5RIC
    Rich M5RIC Member ✭✭✭

    I raised a support ticket for this and was told it was part of defect G7368 which was still pending, do you know when this is being fixed?

  • Darryl
    Darryl Member ✭✭

    You are right Mike.

    Not going to re-build the computer to fix this.


  • Trucker
    Trucker Member ✭✭✭

    Have you tried running System File Checker? You could have a system file that is causing this problem. Open a command prompt as Administrator and type: sfc /scannow <enter>

    That has fixed odd problems for me in the past.



  • KD0RC
    KD0RC Member, Super Elmer Moderator

    Thanks for this insight, James. It found some problems on my system that it fixed. I wasn't having any Flex issues, but I feel better about having things cleaned up.

  • KE8AKW
    KE8AKW Member, Unconfirmed ✭✭
    edited November 2022
    I can easily reproduce this 50% of the time by booting up discord right after turning on my pc. If I completely uninstall SmartSDR the issue goes away. There is a issue with Flexs drivers here. Super annoying bug
  • Mike-VA3MW
    Mike-VA3MW Administrator, FlexRadio Employee, Community Manager, Super Elmer, Moderator admin

    As they say, it takes 2 to tango. :)

    You can play your message both ways. If you uninstall Discord do you crash at all? Sadly, it doesn't bring us to the conclusion anyone wants.

    I would uninstall both. Reboot. Install Discord and then install SmartSDR.

    You may also want to open a support ticket so that we can follow up with it further.

  • Darryl
    Darryl Member ✭✭

    FWIW - for my installation the BSOD issue seems to have either gone away or greatly reduced in frequency. Microsoft update giveth and Microsoft update taketh away?

    Will update if/when things change. For now I'm no longer trying to troubleshoot such an intermittent issue.


  • Danny Quist
    Danny Quist Member ✭✭
    I too am getting a lot of BSOD while using Discord. Looking at the issue with WinDBG and the kernel minidumps that are created, I see the following:

    fffff307`4a91f220 fffff805`95c13922 : ffffae86`2ebcdaa0 fffff307`4a91f350 ffffae86`2ebcdd20 ffffae86`2ebcdd20 : portcls!PcDispatchIrp+0xec
    fffff307`4a91f290 ffffae86`2ebcdaa0 : fffff307`4a91f350 ffffae86`2ebcdd20 ffffae86`2ebcdd20 00000000`000000fe : audiodax+0x3922

    This is part of the stack trace generated by the kernel when the BSOD happened. If you notice, there's a line that says audiodax+0x3922 as the source of this issue. Looking at the file, this code appears to be directly related to handing the IRP_MJ_CREATE major function, which is a normal part of Windows Drivers.

    The file located at C:\Program Files\FlexRadio Systems\SmartSDR v3.4.24\64-bit Drivers\RXAudio_DAX\audiodax.sys

    Without access to the source code, this is the part of the Windows driver that handles the IRP_MJ_CREATE request, or when the device is opened. It corresponds to an audio device being opened normally. In the case of Discord, it inspects all your audio devices before starting which is why it reliably triggers the BSOD. There is some way that Discord is opening the device that the FlexRadio DAX device driver can't handle correctly, resulting in a kernel panic. I do not believe that Discord is breaking any API conventions that would cause this error.

    Examining the audiodax.sys file, it looks like it was licensed in 2013 from Eugune Muzychenko's Virtual Audio Cable software at version 4.10 [1]. It has not been updated since. Recent updates would likely merit an update of the existing audiodax code. Examining the differences between the two versions there are a significant number of bug fixes, updates, including modifications for working with Windows versions past 7.

    This is a problem for Flex to fix, likely by updating the licensing/integration of the VAC software. I think Muzychenko has made some licensing changes that may preclude Flex from licensing this in the way it needs. So likely the answer is don't use Discord, and don't use any software that has the likelihood of opening your audio devices.

    [1] https://vac.muzychenko.net/en/customversion.htm
  • KE8AKW
    KE8AKW Member, Unconfirmed ✭✭
    edited September 15
    I think this the best explanation I have seen so far on this issue. I would really like to see this addressed in the future; its very problematic to have to uninstall SmartSDR/DAX just to be able to use in particular, discord or potentially other applications that accesses your audio devices without BSODing with a portcls.sys error. I can't believe that the VAC Flex is using is from 2013, it really should be updated unless theirs a major licensing issue that would make it difficult for them to do.

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