Fix: Microsoft Kernel Wave Audio Mixer Shows a Yellow Exclamation Mark, Error Code Code 19

Fix: Microsoft Kernel Wave Audio Mixer Shows a Yellow Exclamation Mark, Error Code Code 19

Problem Description

A ThinkPad T400 had a fresh installation of a legitimate copy of Windows XP SP3. After the official drivers were installed correctly, there was sound, but after restarting there was no sound anymore. In Device Manager, Microsoft Kernel Wave Audio Mixer showed a yellow exclamation mark, with the error code Code 19. The first few times, updating the driver was enough to restore sound, but later even updating the driver no longer brought the sound back.

Some posts online suggest installing the UAA patch and updating the driver, but neither method worked for me.

Cause Analysis

The failure was probably caused by registry entries related to KMIXER, Microsoft Kernel Wave Audio Mixer, and Realtek. These registry entries may have contained incorrect settings, causing Windows to continue loading audio-related drivers with the wrong configuration after a restart.

Because the sound card depends on the Realtek driver, while Windows XP itself only provides Microsoft Kernel Wave Audio Mixer and does not provide a complete Realtek sound card driver, if Windows automatically detected the device and wrote an incorrect configuration during the first setup, that incorrect configuration could in turn affect later installation of the correct sound card driver.

Solution

Editing the registry is risky. Before doing anything, I recommend selecting "File" -> "Export" in regedit to back up the relevant registry contents. If the system can still create a restore point, it is also best to create one first.

My approach was to delete the incorrect registry contents related to KMIXER, Microsoft Kernel Wave Audio Mixer, and Realtek. One thing to note is that I did not find Realtek High Definition Audio when searching the registry.

The general procedure was as follows:

  1. Open "Run", enter regedit, and open Registry Editor.
  2. Search for kmixer.
  3. Do not only delete values containing kmixer; also delete the entire registry keys that contain those values.
  4. If you encounter a key that you do not have permission to delete, do not simply skip it; adjust the permissions for that key first.
  5. After deletion is complete, restart the computer and let Windows automatically reinstall Microsoft Kernel Wave Audio Mixer.

After deleting the entries, I restarted the computer directly and found that Microsoft Kernel Wave Audio Mixer was still automatically installed, and it worked normally. I then restarted twice more, and the driver installed normally both times. The problem was finally resolved.

Operation Tips

The first time, I only deleted keys containing kmixer, "values" containing kmixer, and values whose data contained kmixer. After restarting, it still did not work. This showed that the deletion had not been thorough enough.

At the time, searching directly for Microsoft Kernel Wave Audio Mixer returned no results, but I later found that Microsoft Kernel Wave Audio Mixer and kmixer were in the same registry key. So I deleted every related "key" that contained kmixer.

The first failure mainly had two causes:

  1. The deletion was not thorough enough. You cannot only delete the kmixer key and values containing kmixer; you should also delete the "keys that contain those kmixer values".
  2. I skipped keys or values when the system reported that I did not have permission. Later I realized that those permission-denied items may have been exactly the key ones.

For example, when I first tried to delete the key {9B365890-165F-11D0-A195-0020AFD156E4}, the system said I did not have permission. The correct approach was to right-click that "key", open the permission settings, add "Full Control" permission for Everyone, and then delete it.

Postscript

If I remember correctly, this problem had existed from the very beginning when XP was installed. In theory, there should have been no problem with the system's algorithm, and I also followed the procedure step by step, yet incorrect registry information was still written. Can computers occasionally make mistakes too, even when the algorithm is correct and the user input is the same?

This issue was probably like this: when the sound card driver was configured for the first time, Windows automatically installed the detected sound card with incorrect settings for some reason, and KMIXER alone could not fully drive this sound card; the incorrect configuration then affected installation of the correct sound card driver. I suspect the problem was caused by this kind of unfortunate chain of events.

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