June 8, 2021 - KB5003671 (Monthly Rollup)
Important: Windows 8.1 and Windows Server 2012 R2 have reached the end of mainstream support and are now in extended support. Starting in July 2020, there will no longer be optional, non-security releases (known as "C" releases) for this operating system. Operating systems in extended support have only cumulative monthly security updates (known as the "B" or Update Tuesday release).
Verify that you have installed the required updates listed in the How to get this update section before installing this update.
For information about the various types of Windows updates, such as critical, security, driver, service packs, and so on, please see the following article. To view other notes and messages, see the Windows 8.1 and Windows Server 2012 R2 update history home page.
Improvements and fixes
This security update includes improvements and fixes that were a part of update KB5003209 (released May 11, 2021) and addresses the following issues:
For more information about the resolved security vulnerabilities, please refer to the new Security Update Guide website.
- Security updates to Windows App Platform and Frameworks, Windows Cloud Infrastructure, Windows Authentication, Windows Fundamentals, Windows Storage and Filesystems, Windows HTML Platform, and Microsoft Scripting Engine.
Known issues in this update
Symptom Workaround Certain operations, such as rename, that you perform on files or folders that are on a Cluster Shared Volume (CSV) may fail with the error, “STATUS_BAD_IMPERSONATION_LEVEL (0xC00000A5)”. This occurs when you perform the operation on a CSV owner node from a process that doesn’t have administrator privilege. Do one of the following:
Microsoft is working on a resolution and will provide an update in an upcoming release.
- Perform the operation from a process that has administrator privilege.
- Perform the operation from a node that doesn’t have CSV ownership.
How to get this update
Before installing this update
We strongly recommend that you install the latest servicing stack update (SSU) for your operating system before you install the latest Rollup. SSUs improve the reliability of the update process to mitigate potential issues while installing the Rollup and applying Microsoft security fixes. For general information about SSUs, see Servicing stack updates and Servicing Stack Updates (SSU): Frequently Asked Questions.
If you use Windows Update, the latest SSU (KB5001403) will be offered to you automatically. To get the standalone package for the latest SSU, search for it in the Microsoft Update Catalog.
Install this update
Release Channel Available Next Step Windows Update and Microsoft Update Yes None. This update will be downloaded and installed automatically from Windows Update. Microsoft Update Catalog Yes To get the standalone package for this update, go to the Microsoft Update Catalog website. Windows Server Update Services (WSUS) Yes This update will automatically sync with WSUS if you configure Products and Classifications as follows:
Product: Windows 8.1, Windows Server 2012 R2, Windows Embedded 8.1 Industry Enterprise, Windows Embedded 8.1 Industry Pro
Classification: Security Updates
For a list of the files that are provided in this update, download the file information for update 5003671.
Source: June 8, 2021—KB5003671 (Monthly Rollup)
Direct download links for KB5003671 MSU file from Microsoft Update Catalog:
Download KB5003671 MSU for Windows 8.1 32-bit (x86) - 347.4 MB
Download KB5003671 MSU for Windows 8.1 64-bit (x64) - 532.1 MB