July 6, 2021—KB5004947 (OS Build 17763.2029) Out-of-band

**6/15/21
IMPORTANT **This release includes the Flash Removal Package. Taking this update will remove Adobe Flash from the machine. For more information, see the Update on Adobe Flash Player End of Support.

**5/11/21
REMINDER **Windows 10, version 1809 reached 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.

**5/11/21
REMINDER **Microsoft removed the Microsoft Edge Legacy desktop application that is out of support in April 2021. In the May 11, 2021 release, 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.

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 page.

Highlights

• Updates a remote code execution exploit in the Windows Print Spooler service, known as “PrintNightmare”, as documented in CVE-2021-34527.

Improvements and fixes

This security update includes quality improvements. Key changes include:

• Addresses a remote code execution exploit in the Windows Print Spooler service, known as “PrintNightmare”, as documented in CVE-2021-34527. After installing this and later Windows updates, users who are not administrators can only install signed print drivers to a print server. By default, administrators can install signed and unsigned printer drivers to a print server. The installed root certificates in the system’s Trusted Root Certification Authorities trusts signed drivers. Microsoft recommends that you immediately install this update on all supported Windows client and server operating system, starting with devices that currently host the print server role. You also have the option to configure the RestrictDriverInstallationToAdministrators registry setting to prevent non-administrators from installing signed printer drivers on a print server. For more information, see KB5005010.
  If you installed earlier updates, only the new fixes contained in this package will be downloaded and installed on your device.

Windows Update ImprovementsMicrosoft 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

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Click or tap to view the known issues

1. Uninstall and reinstall any recently added language packs. For instructions, see Manage the input and display language settings in Windows 10.

2. 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:

3. Go to the Settingsapp > Recovery.

4. Select Get Started under the**Reset this PC **recovery option.

5. 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 toWindows 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