April 22, 2021—KB5001384 (OS Build 17763.1911) Preview

^4/13/21 IMPORTANT Windows 10, version 1809 will reach end of service on May 11, 2021 for devices running the Enterprise, Education, and IoT Enterprise 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 G, HoloLens, and the LTSC editions for Client, Server, and IoT.

^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.

11/17/20 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 1809 update history home page.

Highlights

Updates an issue that resets the speaker configuration when you cancel the speaker configuration wizard.
Updates an issue that prevents you from turning on the flashlight utility when the Camera application is in use.

Improvements and fixes

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

Removes the Microsoft Edge Legacy desktop application that is out of support and installs the new Microsoft Edge. For more information, see New Microsoft Edge to replace Microsoft Edge Legacy with April’s Windows 10 Update Tuesday release.
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 with window activation that occurs when an owned window is removed.
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 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 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).
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 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 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 Azure Active Directory (AAD) Work Accounts to unexpectedly disappear from certain apps such Microsoft Teams or Microsoft Office.
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 in Task Scheduler that causes monthly tasks and tasks scheduled for 0:00 UTC to occur at the wrong time.
Addresses an issue with Windows Virtual Desktop sessions. A blank list of output devices appears in the Windows Sound Settings app when you plug in a new audio device during a session.
Addresses an issue that resets the speaker configuration when you cancel the speaker configuration wizard.
Addresses an issue that prevents you from turning on the flashlight utility when the Camera application is in use.
Addresses an issue that might prevent an application screen from working when using a Remote Desktop ActiveX control that is embedded in an HTML page.
Addresses an issue that fails to apply the “false” setting for the RequirePDC flag in Active Directory Federation Services (ADFS).
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
After installing KB4493509, devices with some Asian language packs installed may receive the error, "0x800f0982 - PSFX_E_MATCHING_COMPONENT_NOT_FOUND."	Uninstall and reinstall any recently added language packs. For instructions, see Manage the input and display language settings in Windows 10. Select Check for Updates and install the April 2019 Cumulative Update. For instructions, see Update Windows 10. Note If reinstalling the language pack does not mitigate the issue, reset your PC as follows: Go to the Settings app > Recovery. Select Get Started under the Reset this PC recovery option. Select Keep my Files. Microsoft is working on a resolution and will provide an update in an upcoming release.
After installing KB5001342 or later, the Cluster Service might fail to start because a Cluster Network Driver is not found.	This issue occurs because of an update to the PnP class drivers used by this service. After about 20 minutes, you should be able to restart your device and not encounter this issue. For more information about the specific errors, cause, and workaround for this issue, please see KB5003571.
After installing updates released April 22, 2021 or later, an issue occurs that affects versions of Windows Server that are in use as a Key Management Services (KMS) host. Client devices running Windows 10 Enterprise LTSC 2019 and Windows 10 Enterprise LTSC 2016 might fail to activate. This issue only occurs when using a new Customer Support Volume License Key (CSVLK). Note This does not affect activation of any other version or edition of Windows. Client devices that are attempting to activate and are affected by this issue might receive the error, "Error: 0xC004F074. The Software Licensing Service reported that the computer could not be activated. No Key Management Service (KMS) could be contacted. Please see the Application Event Log for additional information." Event Log entries related to activation are another way to tell that you might be affected by this issue. Open Event Viewer on the client device that failed activation and go to Windows Logs > Application. If you see only event ID 12288 without a corresponding event ID 12289, this means one of the following: The KMS client could not reach the KMS host. The KMS host did not respond. The client did not receive the response. For more information on these event IDs, see Useful KMS client events - Event ID 12288 and Event ID 12289.	This issue is resolved in KB5009616.

Symptom

Workaround

After installing KB4493509, devices with some Asian language packs installed may receive the error, "0x800f0982 - PSFX_E_MATCHING_COMPONENT_NOT_FOUND."

Uninstall and reinstall any recently added language packs. For instructions, see Manage the input and display language settings in Windows 10.
Select Check for Updates and install the April 2019 Cumulative Update. For instructions, see Update Windows 10.

Note If reinstalling the language pack does not mitigate the issue, reset your PC as follows:

Go to the Settings app > Recovery.
Select Get Started under the Reset this PC recovery option.
Select Keep my Files.

Microsoft is working on a resolution and will provide an update in an upcoming release.

After installing KB5001342 or later, the Cluster Service might fail to start because a Cluster Network Driver is not found.

This issue occurs because of an update to the PnP class drivers used by this service. After about 20 minutes, you should be able to restart your device and not encounter this issue. For more information about the specific errors, cause, and workaround for this issue, please see KB5003571.

After installing updates released April 22, 2021 or later, an issue occurs that affects versions of Windows Server that are in use as a Key Management Services (KMS) host. Client devices running Windows 10 Enterprise LTSC 2019 and Windows 10 Enterprise LTSC 2016 might fail to activate. This issue only occurs when using a new Customer Support Volume License Key (CSVLK).

Note This does not affect activation of any other version or edition of Windows.

Client devices that are attempting to activate and are affected by this issue might receive the error, "Error: 0xC004F074. The Software Licensing Service reported that the computer could not be activated. No Key Management Service (KMS) could be contacted. Please see the Application Event Log for additional information."

Event Log entries related to activation are another way to tell that you might be affected by this issue. Open Event Viewer on the client device that failed activation and go to Windows Logs > Application. If you see only event ID 12288 without a corresponding event ID 12289, this means one of the following:

The KMS client could not reach the KMS host.
The KMS host did not respond.
The client did not receive the response.

For more information on these event IDs, see Useful KMS client events - Event ID 12288 and Event ID 12289.

This issue is resolved in KB5009616.

How to get this update

Before installing this update

Prerequisite:

You must install the April 22, 2021 servicing stack update (SSU) (KB5001407) 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 5001384.

April 22, 2021—KB5001384 (OS Build 17763.1911) Preview

Highlights

Improvements and fixes

Known issues in this update

How to get this update

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Highlights

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Known issues in this update

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How to get this update

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