Microsoft is testing a quieter lock screen and a much-needed stability fix in its latest Windows 11 preview. Insider Preview Build 26220.9606, rolled out to the Beta Channel, sets Weather as the primary lock screen widget and cuts back on recommended clutter.
The update also takes aim at a frustrating crash bug. The build includes an explicit patch for an issue tied to msmpeg2ac3dec.dll, a system library that had been causing certain desktop software and games to shut down unexpectedly.
That repair arrives alongside an official advisory on Microsoft's release health dashboard. Following the September 22, 2026 update designated as KB5124010, the company acknowledged that software relying on AC-3 decoding could quit without warning. That bug hits Windows 11 version 26H2 alongside versions 25H2 and 24H2. According to Microsoft, the flaw mainly penalizes legacy programs that rely on the operating system's built-in Dolby Digital decoder. Modern applications that ship with their own decoding libraries generally skirt the issue.
While Microsoft has not formally stated that the msmpeg2ac3dec.dll patch in Build 26220.9606 is the exact remedy for the KB5124010 bug, the timing and the shared media symptoms point in that direction.
Calmer lock screen defaults
Beyond stability, Microsoft is rethinking what greeted users when waking their machines. The company says the revised lock screen experience aims for a calmer atmosphere. Instead of bombarding people with multiple tiles of suggested content, the interface now keeps weather details front and center.
Users who want more data can still customize their view. The controls reside inside Settings under Personalization and then Lock screen, allowing testers to curate whichever specific cards they want visible before signing in. As typical with preview builds, Microsoft cautions that these experimental tweaks might change or never leave the Insider testing pool.
Build 26220.9606 itself is built on Windows 11 version 25H2 and arrives via an enablement package. Insiders tracking channel movements can view their status through Flight Hub.
For general users dealing with broken legacy software, the wait continues. Microsoft has not scheduled when this patch will reach stable systems, confirming only that a broad resolution is in development for a future general update.
CDFiled by The Computing Desk
Laptops, desktops, processors, graphics cards and the operating systems that run on them.
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