KB5124008 can be uninstalled from Settings:
- Select Start > Settings > Windows Update.
- Select Update history under More options.
- Under Related settings, select Uninstall updates.
- In the list, find 2026-09 Security Update (KB5124008).
- Select it, then choose Uninstall.
If Windows does not start normally, uninstall it from Windows Recovery Environment:
- Open Windows RE.
- Select Troubleshoot > Advanced options > Uninstall Updates.
- Select Uninstall latest quality update.
Important: uninstalling a security update has risks, including reduced protection against known vulnerabilities, possible service disruption, loss of future support, and potential data loss.
For the audio issue after a Windows update, these steps are also supported:
- Go to Start > Settings > Windows Update and select Check for updates.
- Restart the device after installing available updates.
- If audio still fails, open Device Manager > Sound, video and game controllers.
- Right-click the audio device and select Update driver.
- If needed, open the device Properties > Driver tab > Roll Back Driver.
- If audio services are stuck, run services.msc, then restart Windows Audio and Windows Audio Endpoint Builder.
KB5124008 is a known update where some USB Audio Class 1.0 devices might fail to start or produce no sound, including Code 10 in Device Manager. Microsoft states that an out-of-band update KB5129195 partially resolves issues affecting devices using 8-channel or 3D audio modes.