Download the December 2021 Patch Tuesday updates

by Radu Tyrsina
Radu Tyrsina
Radu Tyrsina
CEO & Founder
Radu Tyrsina has been a Windows fan ever since he got his first PC, a Pentium III (a monster at that time). For most of the kids of... read more
Affiliate Disclosure
  • The last round of Patch Tuesday updates of 2021 has finally hit live and here's what we have.
  • Below you will find a changelog for each cumulative update, as well as direct download links.
  • As we expected, a light month with only a few security updates and some minor tweaks as well.

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December is finally here and many users are excited to see what the next big feature update is all about.

Of course, today is also the day the monthly Patch Tuesday updates go live, and as always, they bring a host of new features, improvements, and fixes for the most common Microsoft bugs found over the last month.

Since each cumulative update is different for each version of Windows 10, it would be wrong to talk about a singular changelog, and that is why this article exists.

Not only will we be providing you with a detailed changelog of all the modifications brought to each major version of Windows 10, but we will also be providing you with direct download links from the Windows Update catalog.

Also, because of minimal operations during the holidays and the upcoming Western new year, there won’t be a preview release, known as a C release, for the month of December 2021.

There will be a monthly security release, also known as a B release for December 2021, and normal monthly servicing for both B and C releases will resume in January 2022.

[DIRECT DOWNLOAD LINKS] December 2021 Patch Tuesday

Windows 11

As we all know by now, Windows 11 is Microsoft’s latest operating system, although some years ago the company stated that Windows 10 would be the last OS of the series.

However, now that it’s here, the Redmond tech giant is constantly trying to improve it and address certain issues that users still struggle with.

Cumulative update name


Improvements and Fixes

  • This update contains miscellaneous security improvements to internal OS functionality. No additional issues were documented for this release.
  • This update makes quality improvements to the servicing stack, which is the component that installs Windows updates. Servicing stack updates (SSU) ensure that you have a robust and reliable servicing stack so that your devices can receive and install Microsoft updates.


Windows 10 versions 21H1, 20H2, and 2004

Windows 10 v21H1 is the latest major version of Windows 10, and as such has the most experimental features on it.

Fortunately, most bugs that were first present when it was first made available have been weeded out, and this version of Windows 10 is far more stable.

Note icon
Windows 10, version 2004 has reached end of servicing as of this release on December 14, 2021. To continue receiving security and quality updates, Microsoft recommends that you update to the latest version of Windows 10.

To update to one of the newer versions of Windows 10, we recommend that you use the appropriate Enablement Package KB (EKB). Using the EKB makes updating faster and easier and requires a single restart.

To find the EKB for a specific OS, go to the Improvements and fixes section and click or tap the OS name to expand the collapsible section.

This release also contains updates for Microsoft HoloLens (OS Build 19041.1173) released December 14, 2021. 

Microsoft will release an update directly to the Windows Update Client to improve Windows Update reliability on Microsoft HoloLens that have not updated to this most recent OS Build.

Cumulative update name


Known issues

  • Devices with Windows installations created from custom offline media or custom ISO image might have Microsoft Edge Legacy removed by this update, but not automatically replaced by the new Microsoft Edge. This issue is only encountered when custom offline media or ISO images are created by slipstreaming this update into the image without having first installed the standalone servicing stack update (SSU) released March 29, 2021 or later.
Note icon
Devices that connect directly to Windows Update to receive updates are not affected. This includes devices using Windows Update for Business. Any device connecting to Windows Update should always receive the latest versions of the SSU and latest cumulative update (LCU) without any extra steps. 

  • After installing the June 21, 2021 (KB5003690) update, some devices cannot install new updates, such as the July 6, 2021 (KB5004945) or later updates. You will receive the error message, “PSFX_E_MATCHING_BINARY_MISSING”.
  • After installing this update, when connecting to devices in an untrusted domain using Remote Desktop, connections might fail to authenticate when using smart card authentication. You might receive the prompt, “Your credentials did not work. The credentials that were used to connect to [device name] did not work. Please enter new credentials.” and “The login attempt failed” in red.
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Devices need to be restarted after configuring the special Group Policy. For help, please see How to use Group Policy to deploy a Known Issue Rollback. For general information on using Group Policies, see Group Policy Overview.


Windows 10 version 1909

As the Redmond-based tech company said not long ago, Windows 10, version 1909 reached the end of service on May 11, 2021, for devices running the Home, Pro, Pro for Workstation, Nano Container, and Server SAC editions.

Devices still running this version of the OS will no longer receive monthly security and quality updates that contain protection from the latest security threats.

So, if you still want to receive security and quality updates, Microsoft recommends updating to the latest version of Windows 10.

Cumulative update name


Improvements and Fixes

  • Adds support for the cancellation of daylight savings time for the Republic of Fiji for 2021.
  • Addresses an issue that incorrectly renders some variable fonts.
  • Addresses an issue that occurs when a dialog opens within Internet Explorer.
  • Addresses a known issue that causes error codes 0x000006e4, 0x0000007c, or 0x00000709 when connecting to a remote printer that is shared on a Windows print server.
  • Addresses a known issue that might prevent apps, such as Kaspersky apps, from opening after you attempt to repair or update the apps using the Microsoft Installer (MSI).


Windows 10 version 1809

This version of the OS is outdated and will no longer receive any updates from the tech company. Users that are still running this old version on their devices are strongly advised to choose a more recent one to update to.

If you still want to use Windows 10 and are not willing to upgrade to 11, you don’t have to do so right away. After all, Microsoft announced that the support for Windows 10 will go on until 2025.

Cumulative update name


Improvements and fixes

  • Addresses a known issue that might prevent Microsoft Defender for Endpoint from starting or running on devices that have a Windows Server Core installation. 

Known issues

  • After installing KB4493509, devices with some Asian language packs installed may receive the error, “0x800f0982 – PSFX_E_MATCHING_COMPONENT_NOT_FOUND.”
  • After installing KB5001342 or later, the Cluster Service might fail to start because a Cluster Network Driver is not found.
  • After installing updates released April 22, 2021 or later, an issue occurs that affects versions of Windows Server that are in use as a Key Management Services (KMS) host. Client devices running Windows 10 Enterprise LTSC 2019 and Windows 10 Enterprise LTSC 2016 might fail to activate. This issue only occurs when using a new Customer Support Volume License Key (CSVLK). 
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This does not affect activation of any other version or edition of Windows. 


Windows 10 version 1607

This is one of the older OS versions, that Microsoft first released back in August 2016. Apparently, the Redmond-based tech company still feels like there is room for improvement here.

  • Updates to remove Adobe Flash from your device. 
  • Updates for verifying usernames and passwords.
  • Updates to improve security when Windows performs basic operations.

Cumulative update name


Starting in July 2020, all Windows Updates will disable the RemoteFX vGPU feature because of a security vulnerability. For more information about the vulnerability, seeCVE-2020-1036 and KB4570006. After you install this update, attempts to start virtual machines (VM) that have RemoteFX vGPU enabled will fail, and messages such as the following will appear:

If you re-enable RemoteFX vGPU, a message similar to the following will appear:

  • The virtual machine cannot be started because all the RemoteFX-capable GPUs are disabled in Hyper-V Manager.
  • The virtual machine cannot be started because the server has insufficient GPU resources.
  • We no longer support the RemoteFX 3D video adapter. If you are still using this adapter, you may become vulnerable to security risk. Learn more (

End of servicing

Key end of servicing dates for Windows 10, version 1607:

  • July 2020 – Non-security releases (known as “C” releases) for Windows 10, version 1607.
  • April 9, 2019 – Additional servicing for Windows 10 Enterprise, Education, and IoT Enterprise editions.
  • April 9, 2019 and March 12, 2019 – The final two Delta updates for Windows 10, version 1607.
  • October 9, 2018 – Windows Server 2016 Standard edition, Nano Server installation option, Windows Server 2016 Datacenter edition, and the Nano Server installation option.
  • October 8, 2018 – Windows 10 Mobile, version 1607.
  • April 10, 2018 – Devices running Windows 10 Home or Pro editions.

These are the updates that Microsoft released for Windows 10 via the November 2021 Patch Tuesday event. Was this article helpful to you? Let us know in the comments section below.

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