Emergency Patch: Microsoft Issues Out-of-Band Fix for Broken MSMQ Infrastructure
Microsoft has released an out-of-band update to address a Message Queuing issue that emerged after the December 2025 update.
The newly issued patches apply to Windows 10 22H2 ESU, Windows 10 Enterprise LTSC 2021, Windows 10 LTSB 2016, as well as Windows Server versions from 2008 through 2019. While they incorporate the fixes originally delivered in the December 9, 2025 update, they also resolve a condition that left Message Queuing (MSMQ) in a broken state.
Administrators who have already encountered MSMQ failures can apply this update to restore normal operation.
The issue primarily affected enterprise environments. According to Microsoft, users of the Pro and Home editions were “very unlikely” to be impacted. The root cause was a change that caused MSMQ to require write access in locations typically protected by administrative restrictions. As a result, message queues could stop functioning altogether, often accompanied by vague and largely unhelpful error messages.
As a consequence of the failure, services such as Microsoft Internet Information Services (IIS), along with applications that depend on writing data to message queues, could abruptly cease operating. Even worse, system logs would surface misleading messages like “There is insufficient disk space or memory,” despite ample disk space and RAM being available.
It took Microsoft several days to formally acknowledge the problem. The defect was added to the list of known issues on December 12, 2025, during which time administrators were forced to rely on workarounds—either modifying folder permissions or rolling back the update entirely.
While the out-of-band release ultimately resolves the issue, it once again raises questions about Microsoft’s internal quality assurance processes, especially given how deeply MSMQ is embedded in corporate infrastructure.
The service itself has a long history, dating back to the era of Windows 95 and NT 4. Although modern alternatives exist for new development, MSMQ remains a supported Windows component. Its longevity means that many applications—particularly those operating in environments without reliable direct connectivity—continue to depend on it for data exchange.
Unsurprisingly, affected users expressed strong dissatisfaction: many administrators found themselves fielding customer complaints while critical services were down.
And while the relatively swift fix deserves some credit, the very existence of such a regression reflects poorly on validation and testing practices. MSMQ may lack the glamour of a cloud-native service infused with AI features, but countless organizations still rely on legacy code and applications built around it. Breaking such a foundational component is not a minor oversight—it is a lapse that should never have gone unnoticed.
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