Microsoft has fixed a known issue that caused games and Windows 11 apps using AC-3 (Dolby Digital) audio decoding to crash after installing the September 2026 preview update (KB5124010).
While KB5124010 is an optional update that requires clicking a “Download and install” link (reducing the number of potentially affected Windows users), it installs automatically on devices where the “Get the latest updates as soon as they’re available” option is toggled on.
“In some cases the application can fail to launch, or close without warning. In other cases the application will work normally until certain features are used, such as playing music,” Microsoft said when it acknowledged this issue two weeks ago. “Affected applications may vary and can include games, media players, and certain productivity applications.”
However, it added that many modern apps that don’t use Windows’ built-in audio decoding for this type of encoding aren’t affected, and that modern apps that use the legacy AC-3 codec often include their own audio decoding components.
In a new update to the Windows release health dashboard, Microsoft said the KB5127648 October 2026 Patch Tuesday update addresses this known issue and advised affected users to install it on affected systems running Windows 11 24H2 and later.
“We recommend you install the latest security update for your device as it contains important improvements and issue resolutions, including this one,” it said.
Over the last several years, Microsoft has resolved multiple other audio issues impacting various software and Windows components.
For instance, two years ago it confirmed a bug that caused game audio to unexpectedly jump to full volume when using USB DAC sound systems and blocked Windows 24H2 upgrades on devices with incompatible Intel Smart Sound Technology (SST) audio drivers because of blue screen of death (BSOD) issues.
Last year, in January 2025, Microsoft addressed a similar issue that triggered audio playback problems on Windows 11 24H2 systems with USB audio device drivers and lifted a safeguard hold preventing upgrades because an incompatibility issue caused Bluetooth headsets and speakers to malfunction on systems with Dirac audio improvement software.
More recently, in September, Microsoft released emergency updates to fix another bug that triggered USB audio issues after installing the September 2026 KB5124008 and KB5124012 security updates.
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