Download Cumulative Update KB5006670 for Windows 10 v21H1, v20H2, and v2004

It is now time for Patch Tuesday for October 2021, and Microsoft has released a Cumulative Update KB5006670…

Windows 10 Cumulative Update KB5006670

It is now time for Patch Tuesday for October 2021, and Microsoft has released a Cumulative Update KB5006670 for Windows 10 versions 21H1, 20H2, and 2004. The same update applies to all 3 versions. However, this update does not include any new features. Rather, it only makes a single non-security improvement to the operating system.

Installing this update will upgrade your Windows 10 v21H1 to build 19043.1288, v20H2 to build 19042.1288, and v2004 to build 19041.1288.

Let us now see what KB5006670 brings to Windows 10.

Fixes and Improvements

As we mentioned earlier, KB500667 brings only one significant improvement to the OS. It seems that the issue it resolved was so distressful that Microsoft just had to release an update to resolve it.

Installing this update will fix an issue on devices that are subject to Microsoft Exploit Protection for Export Address Filtering (EAF) that prevents certain applications, such as Microsoft Office and Adobe Reader, from running, or causes them to stop responding entirely.

This fix is applicable on Windows 10 v21H1, v20H2, and v2004. No other improvements have been made to each individual version with KB5006670.

However, there are some known issues with it.

Known issues

We know this only fixes a single problem, but how many does it bring? Let’s see:

An issue with the standalone (clean) installation of Windows 10 with this update is causing Microsoft Edge Legacy to be removed. However, it is not being replaced by the new Chromium-based Edge. This occurs only when Windows has a custom offline media or an ISO image installed that does not include the 29th March 2021 SSU update.

Microsoft suggests that you either install the March SSU update through slipstreaming or simply update an existing OS through Windows Update, so you will not be facing this issue. Alternatively, you can simply download and install the new Microsoft Edge if you have already encountered this problem.

Another issue that users might face with this update is that they are unable to install it entirely. This may be because of a previously installed update KB5003690. If that is the case, you can find a workaround for it here in Microsoft’s post.

These issues have been long-continuing with quite a few builds in the past. Therefore, it is safe to say that KB5006670 does not bring any new issues to Windows 10 that Microsoft is currently aware of.

Download and install Windows 10 Update KB5006670

Offline Installers

For Windows 10 Version 21H1

Download KB5006670 for Windows 10 Version 21H1 64-Bit [619.6 MB]

Download KB5006670 for Windows 10 Version 21H1 32-Bit [290.1 MB]

For Windows 10 Version 20H2

Download KB5006670 for Windows 10 Version 20H2 64-Bit [619.6 MB]

Download KB5006670 for Windows 10 Version 20H2 32-Bit [290.1 MB]

For Windows 10 Version 2004

Download KB5006670 for Windows 10 Version 2004 64-Bit [619.6 MB]

Download KB5006670 for Windows 10 Version 2004 32-Bit [290.1 MB]

To install the update, simply run the downloaded MSU file and Windows will automatically install the update. To download any other updates related to any of the above, please check the Microsoft Catalog.

Windows Update

To install this update via Windows Update, you need to be running Windows 10 version 21H1, 20H2, or 2004. To check your version of the operating system, type in winver in Run and press Enter.

Once confirmed, navigate to the Settings app and then click Windows Update on the left. Then click Check for updates on the right side of the page. Once the scan is finished, KB5006670 will begin to download and install automatically. Once installed, click Restart Now.

Restart now jpg
KB5006670 ready to install

You can then confirm that the update has been installed successfully through winver.

updated jpg
Windows 10 v21H1 updated

Rollback/remove Windows 10 Insider Preview update

If you do not wish to keep the installed preview update for some reason, you can always roll back to the previous build of the OS. However, this can only be performed within the next 10 days after installing the new update.

To roll back after 10 days, you will need to apply this trick.

Cleanup after installing Windows Updates

If you want to save space after installing Windows updates, you can run the following commands one after the other in Command Prompt with administrative privileges:

dism.exe /Online /Cleanup-Image /AnalyzeComponentStore
dism.exe /Online /Cleanup-Image /StartComponentCleanup
DISM Cleanup

Also see:

Subhan Zafar is an established IT professional with interests in Windows and Server infrastructure testing and research, and is currently working with Itechtics as a research consultant. He has studied Electrical Engineering and is also certified by Huawei (HCNA & HCNP Routing and Switching).


  1. James Selas says:

    none of your links to download the file works.

    1. I have checked all the links again. All the links are direct download links and are working fine.

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