June 26, 2019 - KB4509476 (OS Build 15063.1898)

Applies to: Windows 10 version 1703


Reminder: March 12 and April 9 will be the last two Delta updates for Windows 10, version 1703. Security and quality updates will continue to be available via the express and full cumulative update packages. For more information on this change please visit our blog.

Windows 10, version 1703, reached end of service on October 8, 2018. Devices running Windows 10 Home, Pro, Pro for Workstation, and IoT Core editions 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.
IMPORTANT: Windows 10 Enterprise and Windows 10 Education editions will receive one year of additional servicing at no cost.


Windows 10 Mobile, version 1703, reached end of service on June 11, 2019. Devices running Windows 10 Mobile and Windows 10 Mobile Enterprise 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.

Improvements and fixes

This update includes quality improvements. Key changes include:

  • Addresses an issue that may prevent devices from connecting to some Storage Area Network (SAN) devices using Internet Small Computer System Interface (iSCSI) after installing KB4499162. 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.”

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
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.
After installing this update and restarting, some devices with Hyper-V enabled may enter BitLocker recovery mode and receive an error, "0xC0210000". For a workaround for this issue, please see KB4505821.

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

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

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 4509476.


Source: https://support.microsoft.com/en-us/help/4509476

Direct download links for KB4509476 MSU file from Microsoft Update Catalog:

Download KB4509476 MSU for Windows 10 v1703 32-bit (x86) - 794.6 MB

Download KB4509476 MSU for Windows 10 v1703 64-bit (x64) - 1325.9 MB