Microsoft rushes an out-of-band update for Message Queuing bug
Summary
Microsoft has released an out-of-band (OOB) update to fix a Message Queuing (MSMQ) issue introduced by the December 2025 Windows update. The patch targets Windows 10 22H2 ESU, Windows 10 Enterprise LTSC 2021, Windows 10 LTSB 2016 and multiple Windows Server releases from 2008 through 2019. The bug forced MSMQ to require write access to areas usually restricted by admin permissions, which could stop queuing, break services such as IIS, and generate misleading “There is insufficient disk space or memory” errors despite sufficient resources. Microsoft added the problem to its known-issues list on 12 December 2025; admins have been using workarounds (permission tweaks or rollbacks) until this OOB fix became available. While the update resolves the fault, it highlights shortcomings in validation for legacy components that many enterprises still depend on.
Key Points
- Microsoft released an out-of-band patch to fix MSMQ breakage caused by the December 2025 update.
- Affected systems include Windows 10 (22H2 ESU, LTSC/LTSB) and Windows Server editions from 2008 to 2019.
- Root cause: a change that required MSMQ write access to normally restricted storage locations.
- Symptoms included service failures (for example IIS) and misleading “insufficient disk space or memory” logs.
- Workarounds used by administrators were modifying folder permissions or rolling back the December update until the OOB patch arrived.
Context and relevance
MSMQ is a decades-old component still used by many enterprise applications where direct connectivity isn’t possible. Although not flashy, it underpins critical integration and legacy systems. Breaking it disrupted production services and customer-facing systems, so this fix is important for IT teams. The incident also underscores the risk of regressions in updates and the need for more rigorous testing when changes affect legacy subsystems.
Why should I read this?
If you manage Windows servers or enterprise applications, this is one to skim straight away — your queues might be silently broken. Install the OOB patch or at least check affected hosts; it saves you dealing with angry users and awkward post-mortems. Microsoft fixed it quickly, but it’s worth a couple of minutes to make sure your services aren’t queuing trouble.
Author style
Punchy: Quick fix, but a sloppy slip-up — especially for something so widely relied upon. If you run Windows in business, the details matter; read on if you’re responsible for infrastructure health.