Table of contents
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Release Date:

20/10/2020

Version:

1903-OS Build 18362.1171 and 1909-OS Build 18363.18363.1171

IMPORTANT Release notes are changing! To learn about the new URL, metadata updates, and more, see What’s next for Windows release notes.

IMPORTANT Windows 10, version 1903 will reach end of servicing on December 8, 2020. To continue receiving security and quality updates, Microsoft recommends that you update to the latest version of Windows 10. If you want to update to Windows 10, version 1909, you must use the Enablement Package KB4517245(EKB). Using the EKB makes updating faster and easier and requires a single restart. For more information, see Windows 10, version 1909 delivery options.

IMPORTANT Starting in July 2020, we will resume non-security releases for Windows 10 and Windows Server, version 1809 and later. There is no change to the cumulative monthly security updates (also referred to as the "B" release or Update Tuesday release). For more information, see the blog post Resuming optional Windows 10 and Windows Server non-security monthly updates.

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, 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 (https://go.microsoft.com/fwlink/?linkid=2131976)”

What's new for Windows 10, version 1909 and Windows 10, version 1903 release notes

Windows 10, versions 1903 and 1909 share a common core operating system and an identical set of system files. As a result, the new features in Windows 10, version 1909 were included in the recent monthly quality update for Windows 10, version 1903 (released October 8, 2019), but are currently in a dormant state. These new features will remain dormant until they are turned on using an enablement package, which is a small, quick-to-install “master switch” that simply activates the Windows 10, version 1909 features.

To reflect this change, the release notes for Windows 10, version 1903 and Windows 10, version 1909 will share an update history page. Each release page will contain a list of addressed issues for both 1903 and 1909 versions. Note that the 1909 version will always contain the fixes for 1903; however, 1903 will not contain the fixes for 1909. This page will provide you with the build numbers for both 1909 and 1903 versions so that it will be easier for support to assist you if you encounter issues.

For more details about the enablement package and how to get the feature update, see the Windows 10, version 1909 delivery options blog.

For more information about the various types of Windows updates, such as critical, security, driver, service packs, and so on, please see the following article.

Note Follow @WindowsUpdate to find out when new content is published to the release information dashboard.

Highlights

  • Introducing Meet Now in the Windows 10 Taskbar

    Earlier this year we introduced Meet Now in Skype. Meet Now makes it easy to connect with anyone in as little as two clicks for free and each call can last up to 24 hours. Today, we’re excited to share that we will be extending this capability in Windows 10 by bringing Meet Now right to the taskbar. In the coming weeks,you will be able to easily set up a video call and reach friends and family in an instant by clicking the Meet Now icon in the taskbar notification area. No sign ups or downloads needed.

  • Updates an issue that might prevent a Microsoft Xbox Game Pass user from playing certain games that are eligible for play.

  • Updates a reliability issue that causes the screen to flash constantly.

  • Updates an issue that causes a USB printer port to disappear after restarting when the printer device is turned power off.

Improvements and fixes

This non-security update includes quality improvements. Key changes include:

  • This build includes all the improvements from Windows 10, version 1903.

  • No additional issues were documented for this release.

This non-security update includes quality improvements. Key changes include:

  • Addresses an issue with using Group Policy Preferences to configure the homepage in Internet Explorer.

  • Allows administrators to use a Group Policy to enable Save Target As for users in Microsoft Edge IE Mode.

  • Addresses an issue with untrusted URL navigations from Internet Explorer 11 by opening them in Microsoft Defender Application Guard using Microsoft Edge.

  • Addresses an issue that occurs when using the full suite of developer tools in Microsoft Edge for remote debugging on a Windows 10 device.

  • Addresses an issue that displays a black screen to Windows Virtual Desktop (WVD) users when they attempt to sign in.

  • Addresses an issue that might prevent a Microsoft Xbox Game Pass user from playing certain games that are eligible for play.

  • Addresses an issue that displays nothing on the screen for five minutes or more during the Remote Desktop Protocol (RDP) session.

  • Addresses a reliability issue that causes the screen to flash constantly.

  • Addresses an issue with Dynamic Data Exchange (DDE) that causes a memory leak when multiple clients connect to the same server.

  • Addresses an issue that causes an application to stop responding temporarily, which causes extra z-order operations that affect the Window.Topmost property of a window.

  • Addresses an issue that might cause DDE apps to stop working.

  • Addresses an issue that occurs when you first sign in to an account or unlock an existing user session using Remote Desktop Services (RDS). If you enter an incorrect password, the current keyboard layout changes unexpectedly to the system default keyboard layout. This keyboard layout change might cause additional attempts to sign in to fail or lead to account lockouts in domains with low account lockout thresholds.

  • Addresses an issue with the CleanupProfiles Group Policy object (GPO). After you upgrade the operating system, when you configure the CleanupProfiles GPO, it fails to remove unused user profiles.

  • Addresses an issue that displays the incorrect CPU frequency for certain processors.

  • Addresses a performance issue that occurs when PowerShell reads the registry to check if the ScriptBlockLogging registry key is in the registry.

  • Addresses an issue that randomly changes the time offset of the time format returned by the command WMIC.exeOS Get localdatetime/ value.

  • Addresses an issue that prevents Microsoft User Experience Virtualization (UE-V) from assigning the Microsoft Outlook Signatures.

  • Addresses an issue that prevents Hybrid Azure Active Directory joined devices from updating portal information when a device name or Windows version changes.

  • Addresses an issue that causes Windows to stop working and generates error 0x17. This issue occurs when Windows Defender Device Guard is enabled and a driver is loaded with a 4K Microsoft Portable Executable (PE) header.

  • Adds a new Microsoft Event Tracing for Windows (ETW) provider named "Microsoft-Antimalware-UacScan". This ETW provider reports the details of the context for each User Account Control (UAC) request in the ETW provider manifest.

  • Addresses issue that causes a USB printer port to disappear after restarting when the printer device is turned power off.

  • Addresses an issue that causes stop error 0xd1 in msiscsi.sys. This issue occurs when moving certain arrays from one cluster node to another.

  • Addresses an issue that prevents Windows Update and Microsoft Store from connecting to peers over virtual private networks (VPN) for downloads.

  • Adds functionality that shows a preview of the features and capabilities included in an update when a new update is offered to your device. On the Windows Update page (Start > Settings > Update & Security > Windows Update), there’s an option to “See what’s in this update.”

  • Adds support for the Transport Layer Security (TLS) 1.1 and 1.2 protocols when connecting to SQL Server using the data providers in Microsoft Data Access Components (MDAC). 

  • Addresses an issue with SQL Server that might cause performance issues if you configure a Linked Server provider to load out-of-process.

  • Addresses an issue that might degrade Windows performance and prevent the LanmanServer service from starting when third-party software uses LanmanServer custom file system controls (FSCTL).

  • Addresses an issue with deduplication that causes long wait times on Resilient File System (ReFS) Cluster Shared Volumes (CSV).

  • Addresses an issue that might prevent some applications from behaving correctly. This occurs when you publish them as Remote Application Integrated Locally (RAIL) applications using RDS and change the docking for an AppBar window.

  • Addresses an issue with a deadlock in the Transmission Control Protocol/Internet Protocol (TCPIP) driver that causes the operating system to stop working or stop responding.

  • Addresses an issue that causes the Routing and Remote Access Service (RRAS) to stop responding for new connections. However, RRAS continues working for existing connections.

  • Addresses an issue that causes the RRAS administrator Microsoft Management Console (MMC) to stop responding randomly when you are performing administrative tasks or at startup.

  • Addresses an issue that might cause an application to stop working when you open the application.

  • Improves the Windows Server Storage Migration Service by:

    • Adding inventory validation.

    • Improving retransfer performance .

    • Resolving multiple issues, including reliability issues.

    • Verifying that source machines have installed the current update.
      For more information, see Storage Migration Service October 2020 Update.

If you installed earlier updates, only the new fixes contained in this package will be downloaded and installed on your device.

Windows Update Improvements

Microsoft has released an update directly to the Windows Update client to improve reliability. Any device running Windows 10 configured to receive updates automatically from Windows Update, including Enterprise and Pro editions, will be offered the latest Windows 10 feature update based on device compatibility and Windows Update for Business deferral policy. This doesn't apply to long-term servicing editions.

Known issues in this update

Symptom

Workaround

When updating to Windows 10, version 1903 or Windows 10, version 1909 from any previous version of Windows 10, you might receive a compatibility report dialog with "What needs your attention" at the top and the error, "Continuing with the installation of Windows will remove some optional features. You may need to add them back in Settings after the installation completes." You might receive this compatibility warning when LOCAL SYSTEM accounts are blocked in a firewall from accessing the internet via HTTP. This is caused by the Windows 10 Setup Dynamic Update (DU) being unable to download required packages.

This issue is resolved in KB4579919.

System and user certificates might be lost when updating a device from Windows 10, version 1809 or later to a later version of Windows 10. Devices will only be impacted if they have already installed any Latest cumulative update (LCU) released September 16, 2020 or later and then proceed to update to a later version of Windows 10 from media or an installation source which does not have an LCU released October 13, 2020 or later integrated. This primarily happens when managed devices are updated using outdated bundles or media through an update management tool such as Windows Server Update Services (WSUS) or Microsoft Endpoint Configuration Manager. This might also happen when using outdated physical media or ISO images that do not have the latest updates integrated.

Note Devices using Windows Update for Business or that connect directly to Windows Update are not impacted. Any device connecting to Windows Update should always receive the latest versions of the feature update, including the latest LCU, without any extra steps.

 This issue is resolved in KB4592449.

How to get this update

Before installing this update

Microsoft strongly recommends you install the latest servicing stack update (SSU) for your operating system before installing the latest cumulative update (LCU). SSUs improve the reliability of the update process to mitigate potential issues while installing the LCU. For general information about SSUs, see Servicing stack updates and Servicing Stack Updates (SSU): Frequently Asked Questions.

If you are using Windows Update, the latest SSU (KB4577670) 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 or Microsoft Update

Yes

Go to Settings > Update & Security > Windows Update. In the Optional updates available area, you’ll find the link to download and install the 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)

No

You can import this update into WSUS manually. See the Microsoft Update Catalog for instructions.

File information

For a list of the files that are provided in this update, download the file information for cumulative update 4580386

Note Some files erroneously have “Not applicable” in the “File version” column of the CSV file. This might lead to false positives or false negatives when using some third-party scan detection tools to validate the build.

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