Windows Update KB5121003 breaking thermal printers

Peter Scherer 0 Reputation points
2026-09-01T17:15:45.57+00:00

WIndows update KB5121003, Windows 11 24H2/25H2 cumulative update (builds 26100.9168/26200.9168) is breaking thermal printing. Specfically Cognitive TPG thermal printers. I have around 450 reports as of deployment of the update on August 13th. I have seen no other reports online besides a thread in reddit on this. The same reddit threat poster had tried EPSON, TSC, and Avery printers.

So far to mitigate it we have uninstalled the update and blocked it from deploying, that is fixing it in the short-term. But we are not receptive to continuing to do this as this is a security update.

Have reached out to Printer manufacturer(Cognitive TPG) to see if they have anything on their end with the driver. But as the driver works just fine prior to the update, and post uninstall we don't believe it to be an issue with the driver.

Windows for business | Windows Client for IT Pros | Devices and deployment | Other
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  1. Allan Solomon Mejia 7,915 Reputation points
    2026-09-02T18:44:10.39+00:00

    Hello @Peter Scherer

    Your uninstall/retest result is useful evidence, especially with ~450 affected deployments. However, as of September 2, Microsoft’s KB5121003 known-issues section does not list thermal printer failures; the currently documented issue relates to certain games/peripheral drivers.

    Since removing KB5121003 restores printing and reinstalling it reproduces the problem, treat this as a potential update regression and report it to Microsoft rather than assuming the Cognitive TPG driver is solely responsible.

    For affected systems, capture the printer model/driver version, connection type (USB/network), PrintService event logs, Windows build, and a before/after KB5121003 reproduction. Submit this through Feedback Hub (Win+F) and, with this number of affected endpoints, open a Microsoft support case so the Windows printing team can investigate.

    I agree with temporarily pausing deployment as a mitigation, but because KB5121003 is a security update, I don't recommend keeping it blocked longer than necessary without Microsoft guidance.

    Reference: KB5121003 release notes and known issues

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