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).
IMPORTANT Starting in July 2020, all Windows Updates will disable the RemoteFX vGPU feature because of a security vulnerability. For more information about the vulnerability, see CVE-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:
- “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.”
If you re-enable RemoteFX vGPU, a message similar to the following will appear:
- "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 (https://go.microsoft.com/fwlink/?linkid=2131976)”
Improvements and fixes
This security update includes improvements and fixes that were a part of update KB4577066 (released September 8, 2020) and addresses the following issues:
- Corrects the end date for daylight savings time (DST) in 2021 for the Fiji Islands. For more information, see DST correction in Windows for the Fiji Islands: October 13, 2020.
- Addresses an issue where Group Policy recursively deletes critical files when the "Delete local user profile policy" is enabled.
- Addresses an issue in which a Null port is created through the user interface.
- Adds a notification to Internet Explorer 11 that informs users about the end of support for Adobe Flash in December 2020. For more information, see KB4581051.
- Addresses an issue with Microsoft Edge IE Mode that occurs when you enable Configure enhanced hang detection for Internet Explorer mode in Microsoft Edge.
- Allows administrators to disable JScript in specific security zones.
- Security updates to Windows App Platform and Frameworks, Windows Graphics, Windows Shell, Windows Silicon Platform, Windows Cloud Infrastructure, Windows Fundamentals, Windows Authentication, Windows Virtualization, Windows Kernel, Windows Core Networking, Windows Network Security and Containers, Windows Remote Desktop, and Windows SQL components.
For more information about the resolved security vulnerabilities, please refer to the Security Update Guide.
Known issues in this update
|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.
When installing a third-party driver, you might receive the error, “Windows can’t verify the publisher of this driver software”. You may also see the error “No signature was present in the subject” when attempting to view the signature properties using Windows Explorer.
This issue occurs when one or more of the following is present in a driver package:
If this happens you should contact the driver vendor or device manufacturer (OEM) and ask them for an updated driver to correct the issue.
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.
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 ProClassification: Security Updates
For a list of the files that are provided in this update, download the file information for update 4580347.