Microsoft Asks IT Admins to Contact for Fix Related to Windows IIS Failure Issues
Microsoft has identified an issue with its December 2025 Windows security update (KB5071546, OS Build 19045.6691), which is causing failures in Message Queuing (MSMQ) and resulting in crashes of Internet Information Services (IIS) sites.
Microsoft has identified an issue with its December 2025 Windows security update (KB5071546, OS Build 19045.6691), which is causing failures in Message Queuing (MSMQ) and resulting in crashes of Internet Information Services (IIS) sites.
The problem, first reported on December 12 and updated on December 16, occurs under load conditions, particularly in clustered setups, disrupting critical messaging workflows. Affected users report that MSMQ queues become inactive, preventing applications from writing messages. IIS-hosted sites display "Insufficient resources to perform operation" errors, halting services despite available disk space and memory.
Errors include the inability to create message files such as C:\Windows\System32\msmq\storage*.mq . Logs may incorrectly indicate "insufficient disk space or memory."
The root cause is recent changes in MSMQ's security model, which have tightened NTFS permissions on the C:\Windows\System32\MSMQ\storage folder. This requires MSMQ users to have explicit write access, previously limited to administrators, leading to API failures.
Affected users report that MSMQ queues become inactive, preventing applications from writing messages.
This issue largely affects enterprise IT systems, particularly Windows Server (2019, 2016, 2012 R2, and 2012) and Windows 10 versions (22H2, 21H2, 1809, and 1607). Consumer setups, such as Windows Home or Pro editions on personal devices, are not significantly impacted.
Microsoft acknowledges the issue on its support portal, linking it to permission changes in the patch released on December 9. Currently, no public fix is available, and IT teams must contact Microsoft Support to implement a workaround that restores folder access without compromising security.
Security teams are advised to scan environments immediately using tools like PowerShell’s Get-HotFix or WSUS reports to identify KB5071546 deployments. Rollback is an option for non-clustered systems, although clustered systems face data loss risks.
As threats such as ransomware and supply-chain attacks persist, update-induced disruptions emphasize the need for staged testing. Microsoft is working towards a resolution, and proactive contact with support is recommended to avoid extended downtime.
Based on reporting by Cyber Security News.