May 21, 2019—KB4497934 (OS Build OS 17763.529)

Applies to: Windows 10, version 1809Windows Server 2019, all versions

Improvements and fixes


This update includes quality improvements. Key changes include:

  • Allows users to go back to a host browser from a Windows Defender Application Guard (WDAG) container.
  • Addresses an issue with looping redirects between Microsoft Edge and Internet Explorer 11.
  • Updates wininet.dll to prevent the re-creation of File Transfer Protocol (FTP) control sessions.
  • Addresses an issue that may cause Microsoft Edge to hide annotations added to a PDF file, such as inked notes, highlights, and comments.
  • Addresses an issue that removes UserRights policies from all users in a security group when you remove a device from a mobile device management (MDM) server or Microsoft Intune deletes a UserRights policy.
  • Addresses an issue that disconnects a remote desktop session when you lock the session using a third-party credential provider.
  • Addresses an issue that causes Microsoft Office and other applications to prompt for a password after you change a user account password. This issue occurs on hybrid Azure Active Directory (AD) joined systems.
  • Addresses an issue that prevents ActiveX controls from automatically installing through a proxy server.
  • Addresses an issue that prevents you from signing in to a Microsoft Surface Hub device with an Azure Active Directory account. This issue occurs because the previous sign-out did not complete successfully.
  • Addresses an issue that causes a sign-in to fail with the error, “Incorrect Username or password” when using an empty or null password and Windows Defender Credential Guard is enabled.
  • Addresses an issue that may cause a temporary KRB_AP_ERR_MODIFIED Kerberos sign-in failure in applications and services configured to use a Group Managed Service Account (GMSA). This issue occurs after the automatic update of the service account password.
  • Addresses an issue that may prevent BitLocker from encrypting data drives when the "Enforce drive encryption on fixed data drives" Group Policy is configured.
  • Addresses an issue that prevents updates from downloading from a Windows Server Update Services (WSUS) server when a Windows Defender Application Control policy is set to manage which updates can be deployed.
  • Addresses an issue that may cause event 7600 in the Domain Name System (DNS) server event log to contain an unreadable server name.
  • Addresses an issue that fails to record a local user’s last logon time even when the user has accessed the server’s network share.
  • Addresses an issue that prevents NumLock from working properly in a Remote Assistance session when the Remote Assistance window gains and loses focus.
  • Updates time zone information for Morocco.
  • Updates time zone information for the Palestinian Authority.
  • Addresses an issue with the International Components for Unicode (ICU) data, which were not updated for the time zone and the new Japanese Era.
  • Addresses an issue with the "Allow uninstallation of language features when a language is uninstalled." Group Policy.
  • Addresses an issue in which a File Share Witness does not remove Server Message Block (SMB) handles, which causes a server to eventually stop accepting SMB connections.
  • Addresses an issue in which Windows attempts to renew Azure Active Directory (AAD) token certificates when there is no internet connectivity. This issue occurs during AAD authentication and slows the performance of applications.
  • Addresses an issue with scrollLeft in Internet Explorer.
  • Addresses an issue that causes rendering to stop working for <svg> elements.
  • Addresses an issue with Assigned Access deployments (formerly Kiosk Mode) that prevents a user from logging on to an Assigned Access profile. This affects all locales and occurs when the local administrator’s group is not named using the English spelling of “Administrators”. In the Event Viewer, Event 31000 shows the source as “Microsoft-Windows-AssignedAccess/Admin” and displays the error message, “The group used to assign the application can’t be found.”
  • Addresses an issue that prevents a Generation 2 virtual machine from starting on a Windows Server 2019 Hyper-V host. In the Microsoft-Windows-Hyper-V-Worker-Admin event log, Event ID 18560 displays, “VM name was reset because an unrecoverable error occurred on a virtual processor that caused a triple fault.”
  • Addresses an issue with a system that has pre-start kernel Direct Memory Access (DMA) Protection enabled. When you start Windows in safe mode, a blue screen appears with the error, “DRIVER_VERIFIER_DMA_VIOLATION”.
  • Addresses an issue that may cause screen sharing to fail in Skype, Skype for Business, and Microsoft Teams. This occurs because of a port conflict with the reserved port range on devices that have enabled the Hyper-V role.
  • Addresses an issue that causes a delay when loading many unsigned Domain Name System (DNS) zones related to the Domain Name System Security Extensions (DNSSEC) feature. This issue occurs after configuring the following registry setting:

    Path: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\DNS\Parameters

    Setting: EnableFastLoadUnsignedZones

    Type: DWORD

    Value: A value of 1 enables the feature. A value of 0 disables the feature.

    Restart the operating system or the DNS server after changing the registry values.

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

Known issues in this update


Symptom Workaround
After installing this update, there may be issues using the Preboot Execution Environment (PXE) to start a device from a Windows Deployment Services (WDS) server configured to use Variable Window Extension. This may cause the connection to the WDS server to terminate prematurely while downloading the image. This issue does not affect clients or devices that are not using Variable Window Extension.

This issue is resolved in KB4503327.

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:

  • Perform the operation from a process that has administrator privilege.
  • Perform the operation from a node that doesn’t have CSV ownership.
Microsoft is working on a resolution and will provide an update in an upcoming release.
When attempting to print from Microsoft Edge or other Universal Windows Platform (UWP) applications, you may receive the error, "Your printer has experienced an unexpected configuration problem. 0x80070007e."

This issue is resolved in KB4501371.

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

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

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

Internet Explorer 11 may fail to open if Default Search Provider is not set or is malformed.

This issue is resolved in KB4503327.

Devices may have issues connecting to some Storage Area Network (SAN) devices using Internet Small Computer System Interface (iSCSI) after installing this update. You may also receive an error in the System log section of Event Viewer with Event ID 43 from iScsiPrt and a description of “Target failed to respond in time for a login request.” This issue is resolved in KB4509479.

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 more information, see Servicing stack updates.

If you are using Windows Update, the latest SSU (KB4499728) 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

To download and install this update, go to Settings > Update & Security > Windows Update and select Check for updates.

To get the standalone package for this update, go to the Microsoft Update Catalog website.

File information

For a list of the files that are provided in this update, download the file information for cumulative update 4497934