June 11, 2019—KB4503279 (OS Build 15063.1868)

Applies to: Windows 10 Version 1703

Improvements and fixes


This update includes quality improvements. Key changes include:

  • Addresses a security vulnerability by intentionally preventing connections between Windows and Bluetooth devices that are not secure and use well-known keys to encrypt connections, including security fobs. If BTHUSB Event 22 in the Event Viewer states, “Your Bluetooth device attempted to establish a debug connection….”, then your system is affected. Contact your Bluetooth device manufacturer to determine if a device update exists. For more information, see CVE-2019-2102 and KB4507623.
  • Addresses an issue that may prevent Internet Explorer 11 from opening if the Default Search Provider is not set or is malformed.
  • Security updates to Microsoft Edge, Internet Explorer, Windows App Platform and Frameworks, Windows Input and Composition, Windows Media, Windows Shell, Windows Server, Windows Authentication, Windows Datacenter Networking, Windows Storage and Filesystems, Windows Virtualization, Internet Information Services, and the Microsoft JET Database Engine.

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

For more information about the resolved security vulnerabilities, please refer to the Security Update Guide.

Known issues in this update


Symptom Workaround
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 trying to expand, view, or create Custom Views in Event Viewer, you may receive the error, "MMC has detected an error in a snap-in and will unload it." and the app may stop responding or close. You may also receive the same error when using Filter Current Log in the Action menu with built-in views or logs. Built-in views and other features of Event Viewer should work as expected.

To mitigate this issue, see KB4508640.

We are working on a resolution and estimate a solution will be available in late June.

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 (KB4500640) 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

This update will be downloaded and installed automatically from Windows Update. 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 4503279