PrintNightmare Fix Doesn't Agree With Some Printers

Microsoft's patch addresses the issue, but it's also causing connection errors

The PrintNightmare security vulnerability that left Windows systems open to attack has been patched, but the update is causing a new problem with certain types of printers.

Microsoft says that the KB5004945 patch for the PrintNightmare exploit, caused by a vulnerability with Windows Print Spooler, is working as intended. However, now some users are reporting that the security update is causing connection errors with their printer—most notably Zebra label printers. Microsoft says that the connection errors are due to changes in the overall update and are not a part of the PrintNightmare fix.

Laser printer with documents in office

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"Our investigation has shown that the OOB security update is working as designed and is effective against the known printer spooling exploits and other public reports collectively being referred to as PrintNightmare," Microsoft wrote in its blog update, "All reports we have investigated have relied on the changing of default registry setting related to Point and Print to an insecure configuration."

Businessman working on computer in office

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In a statement to The Verge, Zebra recommends uninstalling the KB5004945 update until the company can issue its own update.

Microsoft recommends installing the CVE-2021-34527 security update immediately to eliminate the threat of a potential Windows Print Spooler exploit. Once installed, you should check your registry settings as documented in the update advisory. You'll be looking for three different registry keys:

  • HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows NT\Printers\PointAndPrint,
  • NoWarningNoElevationOnInstall, and
  • UpdatePromptSettings.

Make sure each of the keys is set to zero (0), or are simply not present, and you should be good to go.

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