KB5004945 Out-Of-Band Update for Windows 10 21h1, 20h2, and 2004

Microsoft releases a new non-security update for Windows 10 21h1, 20h2, and 2004 users titled “KB5004945”. Though an out-of-band update is optional in nature, this patch is mandatory and will be downloaded automatically without even notifying you about it. 

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With this, the company is aiming to resolve a vulnerability inside the Print Spooler service. If left unresolved, a hacker can easily exploit the loophole to serve his/her purpose. Besides resolving the printing issue, this update increases the existing OS Build number to 1904x.1083 where, x varies from 1 to 3 for versions 21h1, 20h2, and 2004. 


KB5004945 Changelog

Since this is an out-of-band update, you may skip this as well. However, if you do install it, you will get the following fixes and improvements –

  • This update addresses a remote code execution exploit in the Windows Print Spooler service. The exploit was widely known as “PrintNightmare” that you can find inside CVE-2021-34527. With this out-of-band update, non-administrator accounts may install only signed print drivers to a print server. The company has recommended to download and install this on all supported Windows Clients or Server Operating systems including those that currently host the print server role. 

Note: Installing this will create a new entry on the registry i.e. “RestrictDriverInstallationToAdministrators”. One may edit this registry to prevent non-admin accounts from installing signed printer drivers on a print server. To know more about this CVE, read the knowledge base KB5005010.

Known Issues on KB5004945 

Here are the key issues that you may encounter after installing this out-of-band update –

  • Problems entering Kanji characters in an app that automatically allows the input of Furigana characters. As of now, there is no solution available. Microsoft is working on this bug and may provide a resolution in an upcoming release. 
  • If you had installed Windows 10 OS using ISO file or custom offline media, the legacy Microsoft Edge will be removed after applying this patch update. You may solve this by manually installing the new Microsoft Edge.

How to Get this update  

You can get this patch update by following either of the below channels –

  1. Windows Update: The update will get installed automatically on your device, so you need not worry about it. In case not, visit Settings > Update & Security, and hit Check for updates. 
  2. Microsoft Update Catalog: As usual, you may download the standalone package by visiting the official site. When you get the file in the file format .msu, double-click over it to install it on your device. 
  3. Windows Server Update Services: The update will automatically sync with WSUS if you configure Products and Classifications as follows:
    • Product: Windows 10, version 1903 and later
    • Classification: Security Updates

Release Note

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