TL;DR
Microsoft released an out-of-band update to address a Message Queuing (MSMQ) problem introduced by its December 2025 update. The fix targets enterprise SKUs and server editions and restores MSMQ without leaving it in a nonfunctional state.
What happened
Microsoft pushed an out-of-band (OOB) update after a December 2025 change caused Message Queuing (MSMQ) to fail in some environments. The emergency patch, aimed at several Windows 10 enterprise builds (22H2 ESU, Enterprise LTSC 2021, LTSB 2016) and Windows Server releases from 2008 through 2019, includes the prior December 9 fixes while preventing MSMQ from being left unusable. The issue primarily affected enterprise deployments; Microsoft said Pro and Home users were very unlikely to see the problem. The root cause was a change that required MSMQ to write to areas normally protected by administrative restrictions, which could halt queuing and disrupt services and applications that rely on it — in some cases bringing IIS and queue‑dependent apps offline. During the interval before the OOB update Microsoft added the problem to its known issues on December 12, and administrators had to apply temporary workarounds such as adjusting folder permissions or rolling back the December update.
Why it matters
- Many enterprises still run legacy systems and services that depend on MSMQ, so disruption can affect critical internal workflows.
- The bug could cause unrelated services (for example IIS) and queue‑dependent applications to fail, increasing operational risk.
- Administrators were forced to deploy emergency mitigations or rollbacks, adding support overhead and potential downtime.
- The incident raises questions about update validation for components that remain widely used in corporate environments.
Key facts
- Microsoft released an out-of-band update to fix an MSMQ issue introduced by the December 2025 update.
- The patch covers Windows 10 22H2 ESU, Windows 10 Enterprise LTSC 2021, Windows 10 LTSB 2016, and Windows Server versions from 2008 to 2019.
- The OOB update contains the fixes from the December 9, 2025 update and prevents MSMQ from being left nonfunctional.
- Microsoft said users on Pro and Home editions were 'very unlikely' to encounter the problem.
- The issue stemmed from a change that required MSMQ to have write access to areas usually restricted by administrative permissions.
- When the bug manifested, message queuing could stop processing and services that depend on queues could fail, sometimes producing misleading error logs indicating insufficient disk or memory.
- Microsoft added the problem to its known issues list on December 12, 2025, before releasing the OOB update.
- During the window before the fix, administrators used workarounds such as modifying folder permissions or rolling back the update to restore services.
What to watch next
- Whether administrators deploy the out-of-band update broadly across affected enterprise systems.
- Microsoft guidance or follow-up notes clarifying long-term mitigations and any additional updates.
- not confirmed in the source: Whether Microsoft will change its validation or quality control processes for updates that touch legacy components like MSMQ.
Quick glossary
- Message Queuing (MSMQ): A Windows component that enables applications to send messages to queues for reliable, asynchronous communication, often used in legacy enterprise systems.
- Out-of-band update (OOB): A software patch released outside the normal update schedule to address a significant or emergent problem.
- Internet Information Services (IIS): Microsoft's web server software used to host websites and web applications on Windows servers.
- Known issue: A documented problem Microsoft acknowledges affecting users after a specific update or release.
Reader FAQ
Is there a fix for the MSMQ problem?
Yes. Microsoft released an out-of-band update that resolves the Message Queuing issue.
Which Windows versions are affected?
Affected editions include Windows 10 22H2 ESU, Windows 10 Enterprise LTSC 2021, Windows 10 LTSB 2016, and Windows Server 2008 through 2019.
Were consumer versions impacted?
Microsoft said users on Pro and Home editions were very unlikely to encounter the issue.
What temporary workarounds were used?
Administrators either granted modified permissions to the storage folder used by MSMQ or rolled back the December update until the OOB patch was available.
Will Microsoft change its update validation practices?
not confirmed in the source
PATCHES 9 Microsoft rushes an out-of-band update for Message Queuing bug Redmond gets in early for the twelve whoopsies of Christmas Richard Speed Tue 23 Dec 2025 // 16:37 UTC Microsoft has hustled out…
Sources
- Microsoft rushes an out-of-band update for Message Queuing bug
- Microsoft fixes Message Queuing issue in new update
- Message Queuing Problem after December Patch
- Regarding problems with "MSMQ" in the December 2025 …
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