October 26, 2021—KB5006738 (OS Builds 19041.1320, 19042.1320, and 19043.1320) Preview

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

• This build includes all the improvements from Windows 10, version 2004.

• No additional issues were documented for this release.

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

• This build includes all the improvements from Windows 10, version 2004.

• No additional issues were documented for this release.

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

• Addresses an issue that prevents you from accessing the pre-provisioning page during the out-of-box experience (OOBE). This issue occurs when the credentials page for signing in to Azure Active Directory appears, and you press the Windows key five times.

• Adds a feature that facilitates certain cross-browser data transfers.

• Addresses an issue with Assigned Access kiosks that are configured with Microsoft Edge as a kiosk application. These kiosks might sometimes fail to restart Microsoft Edge if users close the browser window.

• Addresses an issue in which the use of App-V intermittently causes black screens to appear when signing in on the credentials page.

• Addresses an issue that might prevent subtitles from displaying for certain video apps and streaming video sites.

• Addresses an issue that prevents Windows 10 virtual private network (VPN) users from connecting to Windows Server 2019 Routing and Remote Access service (RRAS) servers.

• Addresses an issue that prevents Software-Defined Networking (SDN) virtual machines from working when you configure the Generic Routing Encapsulation (GRE) VPN bandwidth limitation.

• Addresses a Primary Refresh Token (PRT) update issue that occurs when VPN users sign in using Windows Hello for Business when the VPN connection is offline. Users receive unexpected authentication prompts for online resources that are configured for user sign-in frequency (SIF) in Azure Active Directory-Conditional Access.

• Addresses an issue that causes Windows to go into BitLocker recovery after a servicing update.

• Addresses an issue that might cause Kerberos.dll to stop working within the Local Security Authority Subsystem Service (LSASS). This occurs when LSASS processes simultaneous Service for User (S4U) user-to-user (U2U) requests for the same client user.

• Addresses an issue in Code Integrity that might cause a memory leak.

• Enhances Microsoft Defender for Endpoint’s ability to identify and intercept ransomware and advanced attacks.

• Addresses an issue in the OOBE that might cause Windows AutoPilot provisioning to fail.

• Addresses an issue that prevents Kana input mode users from inserting a question mark (?) using the Shift-0 key combination.

• Addresses an issue that sometimes causes the lock screen to appear black if you set up slideshow.

• Addresses a reliability issue with LogonUI.exe, which affects the rendering of the network status text on the credentials screen.

• Addresses an issue that causes Server Message Block (SMB) Query Directory Requests to fail when the buffer size is large.

• Addresses a memory leak issue in lsass.exe on domain controllers in the forest root domain that occurs when you have multiple forests and multiple domains in each forest. The SID-Name mapping functions leak memory when a request comes from another domain in the forest and crosses forest boundaries.

• Addresses an issue with the virtual machine (VM) Load Balancing feature, which ignores a site’s fault domain.

• Addresses a known issue that might prevent the successful installation of printers using the Internet Printing Protocol (IPP).

• Addresses an issue that affects network interface controller (NIC) disconnect and reconnect scenarios and might cause NICs to remain in a failed state.

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

Symptoms	Workaround
Devices with Windows installations created from custom offline media or custom ISO image might have Microsoft Edge Legacy removed by this update, but not automatically replaced by the new Microsoft Edge. This issue is only encountered when custom offline media or ISO images are created by slipstreaming this update into the image without having first installed the standalone servicing stack update (SSU) released March 29, 2021 or later. Note Devices that connect directly to Windows Update to receive updates are not affected. This includes devices using Windows Update for Business. Any device connecting to Windows Update should always receive the latest versions of the SSU and latest cumulative update (LCU) without any extra steps.	To avoid this issue, be sure to first slipstream the SSU released March 29, 2021 or later into the custom offline media or ISO image before slipstreaming the LCU. To do this with the combined SSU and LCU packages now used for Windows 10, version 20H2 and Windows 10, version 2004, you will need to extract the SSU from the combined package. Use the following steps to extract the SSU: Extract the cab from the msu via this command line (using the package for KB5000842 as an example): expand Windows10.0-KB5000842-x64.msu /f:Windows10.0-KB5000842-x64.cab <destination path> Extract the SSU from the previously extracted cab via this command line: expand Windows10.0-KB5000842-x64.cab /f:* <destination path> You will then have the SSU cab, in this example named SSU-19041.903-x64.cab. Slipstream this file into your offline image first, then the LCU. If you have already encountered this issue by installing the OS using affected custom media, you can mitigate it by directly installing the new Microsoft Edge. If you need to broadly deploy the new Microsoft Edge for business, see Download and deploy Microsoft Edge for business.
After installing the June 21, 2021 (KB5003690) update, some devices cannot install new updates, such as the July 6, 2021 (KB5004945) or later updates. You will receive the error message, "PSFX_E_MATCHING_BINARY_MISSING".	For more information and a workaround, see KB5005322.
After installing this update, when connecting to devices in an untrusted domain using Remote Desktop, connections might fail to authenticate when using smart card authentication. You might receive the prompt, "Your credentials did not work. The credentials that were used to connect to [device name] did not work. Please enter new credentials." and "The login attempt failed" in red.	This issue is addressed in KB5007253.
After installing this update, Windows print clients might encounter the following errors when connecting to a remote printer shared on a Windows print server: 0x000006e4 (RPC_S_CANNOT_SUPPORT) 0x0000007c (ERROR_INVALID_LEVEL) 0x00000709 (ERROR_INVALID_PRINTER_NAME) Note The printer connection issues described in this issue are specific to print servers and are not commonly observed in devices designed for home use. Printing environments affected by this issue are more commonly found in enterprises and organizations.	This issue is resolved in KB5007253.