Microsoft has confirmed the KB5124010 audio crash affecting Windows 11. Applications that rely on AC-3 (Dolby Digital) audio decoding can close unexpectedly after the 22 September 2026 update, across versions 24H2, 25H2 and 26H2. Microsoft opened the known issue on 2 October 2026 and has published no workaround and no fix date.
What Microsoft Confirmed on 2 October
Microsoft opened a known issue on its Windows release health dashboard at 15:06 Pacific Time on 2 October 2026 and gave it the status Confirmed. The entry is titled “Applications which require AC-3 audio decoding might close unexpectedly” and names KB5124010, the optional preview update released on 22 September 2026, as the originating update.
In Microsoft’s own wording, after installing the update “some applications which require the decoding of AC-3 (Dolby Digital) audio might close unexpectedly”. AC-3 is the audio format sold under the Dolby Digital name, used in DVDs, broadcast television and older PC games.
The company says the component at fault “is most commonly used in legacy applications that still rely on Windows built-in audio decoding”, and that many modern applications ship their own decoders and will not be affected. Microsoft has not named a single affected application.
Which Windows 11 Versions Are Affected
Three client versions of Windows 11 are listed, and no server release is. The table below reproduces what Microsoft’s entry states as of 7 October 2026.
| Release | Listed as affected |
|---|---|
| Windows 11, version 26H2 | Yes |
| Windows 11, version 25H2 | Yes |
| Windows 11, version 24H2 | Yes (OS Build 26100.9550) |
| Windows 11, version 26H1 | Not listed |
| Windows Server | None |
The absence of version 26H1 is worth noting because that release does appear in other open entries on the same dashboard, including the black-screen issue reported in September. Microsoft has not said whether 26H1 is unaffected or simply not yet assessed, so its omission is not a clearance.
How to Tell Whether This Is Your Bug
The symptom pattern is specific, and Microsoft describes it in terms of what the application was doing rather than which application it was.
- Fails to launch: The program never opens, with no error message.
- Closes without warning: The program opens and then disappears.
- Crashes on a specific action: The program runs normally until a feature that needs the decoder is used. Microsoft gives playing music as its example.
- Category of software: Games, media players and certain productivity applications, according to the entry.
Two other Windows 11 problems from the same weeks are not this one, and the distinction matters because the remedies differ. KB5124010 was already linked to crashes in Battlefield 6 and other anti-cheat games, which Microsoft has never acknowledged in a known issue. Separately, a September security update caused USB Audio Class 1.0 devices to fail, which is a hardware-driver fault with its own partial fix.
How to Remove KB5124010
Microsoft lists no workaround for this issue, so removing the update is the only step the vendor documents at all. KB5124010 is a preview release, which means it was optional and can be uninstalled without removing September’s security fixes.
- Open Settings, then select Windows Update.
- Select Update history.
- Scroll down and select Uninstall updates.
- Find KB5124010 in the list and select Uninstall.
- Restart the device when prompted.
Removing it also removes the fixes that shipped in the same package, including the File History backup repair. Some sites recommend installing a third-party codec pack instead; Microsoft has neither endorsed nor tested that route, and this article does not recommend it.
Why There Is No Known Issue Rollback for This Bug
There is no Known Issue Rollback available for the AC-3 crashes, and the dashboard makes that easy to misread. A Known Issue Rollback, or KIR, is a Microsoft mechanism that switches off a specific code change through Group Policy without removing the whole update.
A KIR package whose filename contains “KB5124010” does exist on the same release health page, and it is offered for the black-screen and desktop-loading issue that originates with a different update. It does nothing for the audio crashes. Administrators who deploy it expecting a fix will see no change.
What 13 October Changes
Two separate things land on 13 October 2026, and together they decide what most readers should do.
First, Microsoft’s entry says the issue affects updates released on 22 September 2026 “and later”. Preview updates carry the non-security fixes that then ship in the following month’s mandatory cumulative update, so the same code is due to reach devices that never installed the optional package unless Microsoft resolves the issue first. Microsoft has not said whether the October cumulative update will contain the fix.
Second, Windows 11 version 24H2 Home and Pro reach end of updates on 13 October 2026. Microsoft’s own release health page states those editions will no longer receive fixes for known issues after that date, and unmanaged devices are moved to version 25H2 automatically. Enterprise and Education editions of 24H2 are on a longer support timeline and are not covered by that cut-off.
What Microsoft Has Not Said
As of 7 October 2026, the entry has not been updated since 15:41 Pacific Time on 2 October, and it remains at Confirmed rather than Mitigated or Resolved. Microsoft states only that “we are working on releasing a resolution for this issue in a future Windows update”.
- No fix date: No build number or month has been given.
- No affected application list: Microsoft names categories, not titles.
- No scale: No estimate of how many devices are affected has been published.
- No 26H1 ruling: The version is neither listed as affected nor declared clear.
Frequently Asked Questions
Does the KB5124010 Audio Crash Affect Everyone Who Installed the Update?
No. Microsoft says the issue only affects applications that ask Windows to decode AC-3 audio, which it describes as mostly legacy software. Applications that include their own audio decoders are not expected to be affected.
Can I Avoid It by Not Installing KB5124010?
For now, yes, because KB5124010 is an optional preview update. Microsoft’s entry covers updates released on 22 September 2026 and later, however, and preview fixes normally roll into the next mandatory cumulative update, so skipping it is not a permanent protection.
Is There a Known Issue Rollback I Can Apply?
Not for this issue. The Known Issue Rollback package listed on the same Microsoft page addresses a black-screen and desktop-loading problem from a different update, not the AC-3 crashes.
Which Windows 11 Versions Did Microsoft List?
Windows 11 versions 26H2, 25H2 and 24H2 on client devices. Microsoft lists no affected Windows Server release, and version 26H1 does not appear in the entry.
When Will Microsoft Fix the AC-3 Audio Crash?
Microsoft has not given a date. The entry says a resolution will come in a future Windows update, and the company says it will provide an update when more information is available.
