Microsoft's KB5004945 update to fix PrintNightmare is breaking some printers

The PrintNightmare vulnerability that was accidentally revealed recently has led to an almost laughable chain of events. After Microsoft suggested a workaround, a third-party released a patch, an official patch was eventually released, and said patch was found to not actually do the job it was supposed to.

The patch is not only ineffective -- although Microsoft disagrees -- it is also, very much in the tradition of patches for Windows, causing issues. People installing the KB5004945 patch report that they then have problems with printing.

See also:

• Microsoft patch for PrintNightmare vulnerability fails to fix critical security flaw
• Microsoft issues emergency patches for critical PrintNightmare security flaw
• Microsoft suggests workarounds for critical, unpatched PrintNightmare exploit

While there are a lot of complaints from people with Zebra printers, other brands also seem to be affected according to people airing their frustrations on Reddit and in support forums.

Microsoft has already acknowledged the problem, pointing out: "After installing this update, you might have issues printing to certain printers. Most affected printers are receipt or label printers that connect via USB".

Acknowledging the issue is one thing, but what people really want is for the problem to be fixed. This is something that Microsoft says it is working on. In an update to the support page for the KB5004945 update, the company says:

This issue is resolved using Known Issue Rollback (KIR). Please note that it might take up to 24 hours for the resolution to propagate automatically to consumer devices and non-managed business devices. Restarting your Windows device might help the resolution apply to your device faster.

Zebra has also issued a statement saying:

We are aware of a printing issue caused by the July 6 Windows "KB5004945" update affecting multiple brands of printers. Microsoft has investigated this issue and plans to release an update addressing the issue within the next 1–2 business days. An immediate way to address the issue is to uninstall the Windows "KB5004945" update or uninstall the affected printer driver and reinstall using Administrative credentials. Long term, we encourage the use of the newer Windows update Microsoft is planning to release. Customers who need assistance regarding Zebra printers may contact our Technical Support Team.

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