July 10, 2018—KB4338819 (OS Build 17134.165)

Applies to: Windows 10, version 1803

Note  This release also contains updates for Microsoft HoloLens (OS Build 17134.165) released July 10, 2018.

Improvements and fixes


This update includes quality improvements. No new operating system features are being introduced in this update. Key changes include:

  • Improves the ability of the Universal CRT Ctype family of functions to correctly handle EOF as valid input. 
  • Enables debugging of WebView content in UWP apps using the Microsoft Edge DevTools Preview app that’s available in the Microsoft Store.
  • Addresses an issue that may cause the Mitigation Options Group Policy client-side extension to fail during GPO processing. The error message is “Windows failed to apply the MitigationOptions settings. MitigationOptions settings might have its own log file” or “ProcessGPOList: Extension MitigationOptions returned 0xea.” This issue occurs when Mitigation Options has been defined either manually or by Group Policy on a machine using Windows Defender Security Center or the PowerShell Set-ProcessMitigation cmdlet. 
  • Evaluates the Windows ecosystem to help ensure application and device compatibility for all updates to Windows.

  • Addresses an issue that prevents devices on the Workstation Pro SKU from receiving the Windows 10, version 1803 update.

  • Security updates to Internet Explorer, Windows apps, Windows graphics, Windows datacenter networking, Windows wireless networking, Windows virtualization, Windows kernel, and Windows Server.

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

For more information about the resolved security vulnerabilities, see the Security Update Guide.

Known issues in this update


Symptom Workaround
After installing this update on a DHCP Failover Server, Enterprise clients may receive an invalid configuration when requesting a new IP address.  This may result in loss of connectivity as systems fail to renew their leases.

This issue is resolved in KB4345421.

After installing this update, some devices running network monitoring workloads may receive the 0xD1 Stop error because of a race condition.

This issue is resolved in KB4345421.

Restarting the SQL Server service may fail occasionally with the error, “Tcp port is already in use”. This issue is resolved in KB4345421.
When an administrator tries to stop the World Wide Web Publishing Service (W3SVC), the W3SVC remains in a "stopping" state, but cannot fully stop or be restarted. This issue is resolved in KB4345421.

After you install any of the July 2018 .NET Framework Security Updates, a COM component fails to load because of “access denied,” “class not registered,” or “internal failure occurred for unknown reasons” errors. The most common failure signature is the following:

Exception type: System.UnauthorizedAccessException

Message: Access is denied. (Exception from HRESULT: 0x80070005 (E_ACCESSDENIED))

This issue is resolved in KB4343909.

How to get 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.

Important When installing both the servicing stack update (SSU) KB4343669 and the latest cumulative update (LCU) from the Microsoft Update Catalog, install the SSU before installing the LCU.

File information

For a list of the files that are provided in this update, download the file information for cumulative update 4338819