September 24, 2019—KB4516045 (OS Build 17134.1039)

• Updates an issue that may cause a browser to stop working on certain architectures. 
• Updates an issue that prevents Microsoft Narrator from opening.
• Updates an issue that doesn't provide a cursor when you select a text input box using touch. 
• Updates an issue that causes excessive CPU usage when you switch applications or hover over the Taskbar.

This non-security update includes quality improvements. Key changes include:

• Addresses an issue that may cause a browser to stop working on certain architectures. 
• Addresses an issue that prevents Microsoft Narrator from opening when the User Account Controls setting is disabled on the Standard User account. 
• Addresses an issue that fails to provide a cursor when you select a text input element using touch. 
• Addresses an issue with configuring a lock screen image using a Group Policy. If you have enabled AppLocker DLL rules, the image does not change. Instead, you will get a solid blue background. 
• Addresses an issue that causes excessive central processing unit (CPU) usage when users switch applications or hover over the Taskbar. 
• Addresses an issue that prevents an App-V application from opening and displays a network failure error. This issue occurs under certain circumstances, such as when a system's battery is low or there is an unexpected power failure.  
• Addresses an issue that may not preserve changes to the access control policy when upgrading to a newer version of Windows 10. 
• Addresses an issue that may cause authentication to fail for certificate-based authentication when the certificate authentication includes a cname as part of the pre-authentication request. 
• Addresses an issue that prevents a web browser from connecting securely to Windows Server. This occurs when using a client authentication certificate, such as a SHA512-based certificate, and the web browser does not support a signature algorithm that matches the certificate. 
• Addresses an issue that may cause the Local Security Authority Subsystem Service (LSASS) to stop working with an “0xc0000005” error. 
• Changes the default setting for BitLocker when encrypting a self-encrypting hard drive. Now, the default is to use software encryption for newly encrypted drives. For existing drives, the type of encryption will not change. 
• Addresses an issue that prevents the BitLocker recovery key from being successfully backed up to Azure Active Directory. 
• Addresses a possible compatibility issue when Microsoft Defender Advanced Threat Protection (ATP) accesses case-sensitive Server Message Block (SMB) shares. 
• Addresses a rare issue that occurs when the mssecflt.sys driver takes too much space on the kernel stack. This results in the error, "STOP 0x7F: UNEXPECTED_KERNEL_MODE_TRAP", and Parameter 1 is set to “EXCEPTION_DOUBLE_FAULT.” 
• Addresses an issue that leads to excessive memory utilization in Microsoft Defender Advanced Threat Protection (ATP). 
• Improves the detection accuracy of Microsoft Defender ATP Threat & Vulnerability Management. 
• Addresses an issue that gives a Windows Hello for Business user two certificates for authentication during certificate renewal instead of one certificate. 
• Addresses an issue that causes the lsass.exe service to stop working, which causes the system to shut down. This occurs when migrating Data Protection API (DPAPI) credentials using dpapimig.exe with the -domain option.
• Addresses an issue that may give write access to a removable USB disk when a user switches from a privileged user to an unprivileged user.
• Addresses an issue that prevents you from running the Active Directory Diagnostics Data Collector Set from the Performance Monitor for Domain Controllers. This causes the Data Collector Set name to appear empty. Running the Active Directory Diagnostics Data Collector Set returns the error, “The system cannot find the file specified.” Event ID 1023 is logged with the source as Perflib and the following messages:
  • “Windows cannot load the extensible counter DLL “C:\Windows\system32\ntdsperf.dll.”
  • “The specified module could not be found.” 
• Addresses an issue in GetFinalPathNameByHandleW() that prevents Favorites from opening in Internet Explorer 11. This occurs when Favorites are redirected and offline in a client-side caching scenario with enhanced protected mode compatibility (EPM) enabled.
• Addresses an issue with the Origin request header behavior in Internet Explorer when you make cross-origin resource sharing (CORS) requests that use redirected resources in internal subnets.
• Allows auditing of security events for clients managed by mobile device management (MDM) for security monitoring and incident response activities.
• Addresses an issue that causes virtual desktop infrastructure (VDI) environments to show black, flashing rectangles on the screen when using Microsoft Outlook and Microsoft Office.

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

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 (KB4512576) 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

File information

For a list of the files that are provided in this update, download the file information for cumulative update 4516045.