Microsoft security update breaks MSMQ on older Win systems

Microsoft has good news for administrators: while some organizations now pay for security updates on older Windows versions, the inconsistent quality remains free. The company has confirmed that Message Queuing (MSMQ) might fail on some Windows 10 devices and on older versions of Windows Server after installing the December 2025 Security update. The problems include MSMQ queues becoming inactive, Internet Information Services (IIS) sites failing with "Insufficient resources to perform operation" errors, and applications failing to write to queues. To compound the problem, logs are stuffed with misleading errors such as "There is insufficient disk space or memory" despite there being plenty of both. The glitch is actually to do with folder permissions and where MSMQ wants write access. In its documentation for the issue, Microsoft said: "This issue is caused by the recent changes introduced to the MSMQ security model and NTFS permissions on the C:\Windows\System32\MSMQ\storage folder. MSMQ users now require write access to this folder, which is normally restricted to administrators. "As a result, attempts to send messages via MSMQ APIs might fail with resource errors." It also impacts clustered MSMQ environments under load. According to Microsoft, the defect impacts Windows 10 22H2 and earlier (up to 1607), and Windows Server 2012 to 2019. "Individuals using Windows Home or Pro editions on personal devices are very unlikely to experience this issue. This issue primarily affect...