KB5006670 Security Update Windows 10 21H1, 20H2, & 2004

Oct 2021 Security patch for Windows 10 version 21H2/21H1, 2009/2004 is now available for all under the title “KB5006670” at the Microsoft Update Catalog site. This LCU will update the existing OS Build versions to 1904x.1288. The symbol “x” in the build number varies from 1-4 depending upon which version you are currently using. 

Though this Tuesday patch brings a few changes only for Windows 10, they are all totally worth it. Let’s explore the key highlights of this cumulative update in detail –


KB5006670 Changelog

Here are the key changes on the Oct 2021 Security patch update for Windows 10 versions 21H2, 21H1, 2009, and 2004.

  • Works upon an issue that prevents certain applications from opening or starting in Windows 10. These apps include Microsoft Office, Adobe Reader, and a few others. This issue mainly appears on PCs that are subject to Microsoft Exploit Protection for Export Address Filtering (EAF). In certain scenarios, the apps mentioned above do start, however, they stop responding a few moments later.
  • Updates Microsoft HoloLens (OS Build 19041.1168) released October 12, 2021. As per Microsoft, they will soon release an update directly to the Windows Update Client to improve Windows Update reliability on Microsoft HoloLens that have not yet been updated to the most recent OS Build.
  • Apart from the above fixes, this Tuesday’s patch updates the security of all Windows Components and Microsoft services.
  • Moreover, this security patch also makes quality improvements to the servicing stack. Downloading servicing stack updates (SSU) ensures that you have a robust and reliable servicing stack so that your device can receive updates regularly. 

How to Get this patch update

Before you update your system to this Build version, you need to make sure that your PC has already installed May 11, 2021 update i.e. KB5003173 or later LCU. 

This Tuesday patch is now available via all four channels i.e. Windows Update, Windows Update for Business, Update Catalog, and WSUS. 

If you haven’t restricted Windows update from receiving updates regularly, the system will automatically download and install the respective patch update. In case you do, follow the steps below on how to get the KB5006670 LCU manually –

  • First of all, visit the Microsoft Update Catalog site.
  • In the search bar, type “KB5006670”, and hit Enter.
  • This site will then display an array of available updates matching your system architecture.
  • Pick the one that best matches your system configuration, and hit Download.
  • Moving ahead, click the top link to start downloading the standalone package. 
  • When the download completes, double-click on the setup file (.msu) to begin its installation. 
  • Now, follow the on-screen instructions to complete the remaining steps.

I hope you find this article useful to keep your Windows 10 version 21H2/21H1 up to date. 

Release Note

Tip: If you are facing update, activation, or driver issues on your Windows PC, try RESTORO PC Repair Tool. This software will scan your device for potential issues and resolve them automatically.