Windows 11 KB5124008 has a bug that could kill audio on your device and even make your microphone unresponsive. It’s unclear how many users are affected, but Microsoft has now confirmed it’s aware of the issue and says there’s no fix yet.
On September 8, Microsoft rolled out its monthly Patch Tuesday updates with hundreds of security fixes, and KB5124008 is the update rolling out to systems with Windows 11 25H2 or 24H2. It bumps PCs to Windows 11 Build 26200.9445 (25H2) or Build 26100.9445 in case you’re still on 24H2. You can verify the OS Build from Settings > System > About:
So far, Windows Latest has documented several problems with KB5124008. These include Explorer.exe crashes that can leave you with a black screen, broken File History backups, issues with Claude Cowork and other apps that depend on Linux-based virtual machines, Remote Desktop problems, and reports of GPU issues on some AMD systems.
Microsoft has already acknowledged most of these issues, and now the company has confirmed another bug. This one can break audio.
In an updated document spotted by Windows Latest, Microsoft says some audio devices “might fail to start or produce audio” after installing recent Windows updates.
If you’re affected and you boot Windows, you’ll find your audio device isn’t working at all. This can happen immediately after rebooting for the September update. And increasing the volume won’t help because Windows may not be able to start the device in the first place, so even 100% volume won’t produce any sound.
In other cases, if one of the features or changes that causes the audio issue in the first place isn’t turned on on your PC due to the staged rollout, you may not run into the problem immediately. But if your device has the compatibility issue, you could run into it later unless Microsoft patches it.
Microsoft says the Sound settings page may also become unresponsive, which makes it difficult to troubleshoot the problem from Settings. Your next bet is to check Device Manager for logs, and thankfully, it does have something, but it’s not exactly helpful. For the audio device or driver, Device Manager reports the following error:
“This device cannot start (Code 10).”
If you click the Uninstall or Disable option in the hope that audio comes back, it won’t, as the issue originates from Windows Update.
I’ve not been able to determine whether the issue is tied to any particular OEM, but based on the reports we’ve seen so far, I don’t think it’s limited to one manufacturer. Also, it’s not the first time a Windows update has broken audio, so I wouldn’t be surprised if the issue turns out to be wider than Microsoft currently acknowledges.
Windows 11 KB5124008 can also break microphones and multichannel audio
Microsoft specifically ties the confirmed issue to USB Audio Class 1.0 devices, but the problems aren’t necessarily limited to speakers or basic audio playback. One user told me that microphones can also stop working on affected devices.
And even if your audio device starts normally, there’s another issue where Windows can pick up an incorrect audio configuration. For example, if you use multichannel audio features, such as 3D audio or an 8-channel configuration, you might suddenly lose sound.
Microsoft recommends switching the affected device to 2-channel mode as a temporary workaround.
If that doesn’t help, another option would be to use different audio hardware. Based on what we’ve seen so far, wireless audio devices don’t appear to be affected.
Microsoft hasn’t provided a permanent workaround or patch yet, but it confirmed that it’s working on a resolution.
