Release Date:

4/22/2021

Version:

OS Build 18363.1533

4/13/21 IMPORTANT Windows 10, version 1909 will reach end of service on May 11, 2021 for devices running the Home, Pro, Pro for Workstation, Nano Container, and Server SAC editions. After May 11, 2021, these devices will no longer receive monthly security and quality updates that contain protection from the latest security threats. To continue receiving security and quality updates, Microsoft recommends updating to the latest version of Windows 10

We will continue to service the following editions: Enterprise, Education, and IoT Enterprise.

4/13/21 REMINDER Microsoft removed the Microsoft Edge Legacy desktop application that is out of support in March 2021. On April 13, 2021, we installed the new Microsoft Edge. For more information, see New Microsoft Edge to replace Microsoft Edge Legacy with April’s Windows 10 Update Tuesday release.

2/16/21 IMPORTANT As part of the end of support for Adobe Flash, KB4577586 is now available as an optional update from Windows Update (WU) and Windows Server Update Services (WSUS). Installing KB4577586 will remove Adobe Flash Player permanently from your Windows device. Once installed, you cannot uninstall KB4577586. For more details about Microsoft’s plans, see Update on Adobe Flash Player End of Support

12/8/20 REMINDER Windows 10, version 1903 reached 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

11/19/20 For information about Windows update terminology, see the article about the types of Windows updates and the monthly quality update types. To view other notes and messages, see the Windows 10, version 1909 update history home page.

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

Highlights

  • Introducing news and interests on the Windows 10 taskbar With news and interests on the Windows taskbar, you get quick access to an integrated feed of dynamic content, such as news, weather, sports, and more, that updates throughout the day. You can personalize your feed with relevant content tailored for you. In the coming weeks, you will be able to seamlessly peek into your feed directly from the taskbar throughout your day without disrupting your workflow. For more information, see Personalized content at a glance: Introducing news and interests on the Windows 10 taskbar.

  • Updates an issue that causes blank tiles to appear on the Start menu with names such as “ms-resource:AppName” or "ms-resource:appDisplayName".

  • Adds the ability to adjust the amount of idle time before a headset goes to sleep in the Settings app for Windows Mixed Reality. 

  • Updates an issue that generates a stop error when you delete a file or folder from locations that sync with Microsoft OneDrive. 

Improvements and fixes

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

  • Addresses an issue that prevents a site from transitioning out of Microsoft Edge IE Mode when expected.

  • Addresses an issue that fails to remove mandatory profiles completely when you sign out when using the “Delete cached copies of roaming profiles” Group Policy.

  • Addresses an issue that causes blank tiles to appear on the Start menu with names such as “ms-resource:AppName” or "ms-resource:appDisplayName". These blank tiles represent the installed applications and appear for approximately 15 minutes after updating to a newer version of Windows 10. Installing this update prevents these blank tiles from appearing on the Start menu.

  • Addresses an issue with window activation that occurs when an owned window is removed.

  • Addresses an issue with searching after you select File > Open in a 32-bit application. When you click in the search box, the application stops working.

  • Addresses an issue with evaluating the compatibility status of the Windows ecosystem to help ensure application and device compatibility for all updates to Windows.

  • Addresses an issue that includes kernel mode rules for .NET applications in Windows Defender Application Control policies. As a result, the generated policies are significantly larger than necessary.

  • Addresses an issue that causes devices to fail Device Health Attestation.

  • Addresses an issue that causes lsass.exe memory usage to grow until the system becomes unusable. This occurs when Transport Layer Security (TLS) resumes a session.

  • Addresses an issue with a race condition between Task Scheduler and the Workstation Service. As a result, users cannot automatically join a hybrid Azure Active Directory (AAD) domain and error 0x80070490 is generated.

  • Addresses an issue that turns off S Mode when you enable System Guard Secure Launch on a system running Windows 10 in S Mode.

  • Addresses an issue that causes Azure Active Directory (AAD) Work Accounts to unexpectedly disappear from certain apps such Microsoft Teams or Microsoft Office.

  • Addresses an issue that accidently triggers hybrid AAD joining when the Group Policy “Register domain-joined computers as devices” is set to DISABLED. For more information, see Post configuration tasks for Hybrid Azure AD join.

  • Addresses an issue with a partial Service Connection Point (SCP) configuration that causes dsregcmd.exe to stop working. This issue occurs because of a case-sensitive domain ID name comparison that occurs when joining a hybrid Azure Active Directory domain using single sign-on (SSO).

  • Adds the ability to adjust the amount of idle time before a headset goes to sleep in the Settings app for Windows Mixed Reality.

  • Addresses an issue that might generate a stop error when Docker containers run with process isolation.

  • Addresses an issue that causes automatic enrollment and certificate retrieval to fail with the error, “The parameter is incorrect.”

  • Addresses an issue that generates a stop error when you delete a file or folder from locations that sync with Microsoft OneDrive.

  • Addresses an issue with a deadlock in the New Technology File System (NTFS).

  • Improves the Windows Server Storage Migration Service by:

    • Adding support for migration from NetApp FAS arrays to Windows Servers and clusters.

    • Resolving multiple issues and improving reliability.

        For more information, see Storage Migration Service overview.

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

Scroll bar controls might appear blank on the screen and not function after installing this update. This issue affects 32-bit applications running on 64-bit Windows 10 (WOW64) that create scroll bars using a superclass of the USER32.DLL SCROLLBAR window class. This issue also affects HScrollBar and VScrollBar controls that are used in Visual Basic 6 applications and the classes derived from System.Windows.Forms.ScrollBar that are used in .NET Windows Forms applications. A memory usage increase of up to 4 GB might occur in 64-bit applications when you create a scroll bar control.

Scroll bars you create using the SCROLLBAR window class or using the WS_HSCROLL and WS_VSCROLL window styles function normally. Applications that use the scroll bar control that is implemented in COMCTL32.DLL version 6 are not affected. This includes .NET Windows Forms applications that call Application.EnableVisualStyles().

This issue is resolved in KB5003169.

After installing this update or later, the news and interests button in the Windows taskbar might have blurry text on certain display configurations.

This issue is resolved in KB5003698.

How to get this update

Before installing this update

Prerequisite:

You must install the April 13, 2021 servicing stack update (SSU) (KB5001406) or the latest SSU (KB5003155) 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 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 5001396

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