Microsoft December Updates Break Message Queuing Functionality
⚠️ Microsoft has confirmed that its December 2025 security updates are breaking Message Queuing (MSMQ) on affected systems. Machines with KB5071546, KB5071544, or KB5071543 installed — including Windows 10 22H2, Windows Server 2019, and Windows Server 2016 — can experience inactive queues, IIS sites failing with 'insufficient resources', and applications unable to write to queues. Microsoft attributes the failures to security model and NTFS permission changes that require MSMQ users to have write access to C:\Windows\System32\MSMQ\storage; a timeline for a fix has not been provided.
