KB4566425 Servicing stack update for Windows 8.1 - July 14

Servicing stack update for Windows 8.1, RT 8.1, and Server 2012 R2: July 14, 2020

Applies to: Windows 8.1, Windows RT 8.1, Windows Server 2012 R2

Applies to
  • Windows 8.1 for 32-bit systems
  • Windows 8.1 for x64-based systems
  • Windows RT 8.1
  • Windows Server 2012 R2
  • Windows Server 2012 R2 (Server Core installation)

This update makes quality improvements to the servicing stack, which is the component that installs Windows updates. Servicing stack updates (SSU) makes sure that you have a robust and reliable servicing stack so that your devices can receive and install Microsoft updates.

This update also addresses an elevation of privilege vulnerability that exists when the Windows Modules Installer improperly handles file operations. An attacker who successfully exploited this vulnerability could gain elevated privileges. The security update addresses the vulnerability by ensuring the Windows Modules Installer properly handles file operations. For more information, see CVE-2020-1346 | Windows Modules Installer Elevation of Privilege Vulnerability.

How to get this update

Method 1: Windows Update

This update is available through Windows Update. It will be downloaded and installed automatically. 

Method 2: Microsoft Update Catalog

To get the stand-alone package for this update, go to the Microsoft Update Catalog website.

Method 3: Windows Server Update Services

This update is also available through Windows Server Update Services (WSUS).


There are no prerequisites to apply this update.

Restart information

You don't have to restart your computer after you apply this update.

Removal information

Servicing stack updates (SSUs) make changes to how updates are installed and cannot be uninstalled from the device.

Update replacement information

This update replaces the previously released update KB4562253.

Source: https://support.microsoft.com/en-us...ate-for-windows-8-1-rt-8-1-and-server-2012-r2

Direct download links for KB4566425 MSU file from Microsoft Update Catalog:

:arrow: Download KB4566425 MSU for Windows 8.1 32-bit (x86) - 4.8 MB

:arrow: Download KB4566425 MSU for Windows 8.1 64-bit (x64) - 10.5 MBmicrosoft.jpg
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