This month's extended security update for Windows 10 broke Message Queuing (MSMQ), which is typically used by enterprises to manage background tasks.

Microsoft says it identified a fix and is now rolling out an out-of-band update (KB5074976) via Update Catalog to address it.

You won't find the OOB on Windows Update or WSUS, as it's only offered via Update Catalog, but if you are affected, you should download the out-of-band release.

What caused MSMQ issues in Windows 10?

After installing the Windows updates released on December 9, 2025, some users reported issues with the Message Queuing (MSMQ) functionality.

It's likely because of one of the changes Microsoft made to the security features related to MSMQ, which accidentally affected its functionality.

According to the company, issues might lead to message queues becoming inactive, messages about insufficient resources, applications unable to write to message queues, error messages about the message cannot be created, or messages about insufficient disk space or memory

Microsoft tested the update, and it found that this issue also impacts a clustered MSMQ environment under load.

The company argues that regular users with Windows Home or Pro editions on personal devices are very unlikely to experience this issue.

"This issue primarily affects enterprise or managed IT environments," the company explained.

Only PCs signed up for Windows 10 ESU and having issues are supposed to download the OOB update.