September 3, 2020—KB4571744 (OS Build 19041.488) Preview

IMPORTANT Starting in July 2020, we will resume non-security releases for Windows 10 and Windows Server, version 1809 and later. There is no change to the cumulative monthly security updates (also referred to as the "B" release or Update Tuesday release). For more information, see the blog post Resuming optional Windows 10 and Windows Server non-security monthly updates.

IMPORTANT Starting in July 2020, all Windows Updates will disable the RemoteFX vGPU feature because of a security vulnerability. For more information about the vulnerability, seeCVE-2020-1036 and KB4570006. After you install this update, attempts to start virtual machines (VM) that have RemoteFX vGPU enabled will fail, and messages such as the following will appear:

If you re-enable RemoteFX vGPU, a message similar to the following will appear:

“The virtual machine cannot be started because all the RemoteFX-capable GPUs are disabled in Hyper-V Manager.”
“The virtual machine cannot be started because the server has insufficient GPU resources.”

"We no longer support the RemoteFX 3D video adapter. If you are still using this adapter, you may become vulnerable to security risk. Learn more (https://go.microsoft.com/fwlink/?linkid=2131976)”

For more information about the various types of Windows updates, such as critical, security, driver, service packs, and so on, please see the following article.

Note Follow @WindowsUpdate to find out when new content is published to the release information dashboard.

Highlights

Updates an issue that might prevent ActiveX content from loading.
Updates an issue that might cause apps that use the custom text wrapping function to stop working in certain scenarios.
Updates an issue to reduce the likelihood of missing fonts.
Updates an issue that prevents users from reducing the size of a window in some cases.
Updates an issue that causes the touch keyboard to close when you touch any key.
Provides the ability for Dolby Atmos for Headphones and DTS Headphone: X to be used in 24-bit mode on devices that support 24-bit audio.
Updates an issue with a blurry sign in screen.
Updates an issue with Windows Update becoming unresponsive when checking for updates.
Updates an issue that causes File Explorer to stop working when you browse directories of raw images and other file types.
Improves the tablet experience for convertible or hybrid devices in docked scenarios.
Improves the user experience of the Windows Hello enrollment pages for face and fingerprint setup.
Updates an issue that prevents you from unlocking a device if you typed a space before the username when you first signed in to the device.
Updates an issue that causes applications to take a long time to open.
Updates an issue that causes Microsoft Office applications to close unexpectedly when using a Korean IME.
Updates time zone information for the Yukon, Canada.

Improvements and fixes

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

Addresses an issue with pinned Add-ins that cause Microsoft Outlook to become unresponsive.
Provides the ability to sync the Microsoft Edge IE Mode unidirectional session cookie when an administrator configures the session cookie.
Addresses an issue with rendering PeerDist-encoded content in Internet Explorer and Microsoft Edge.
Addresses an issue that might prevent ActiveX content from loading.
Addresses an issue that displays a black screen to Windows Virtual Desktop (WVD) users when they attempt to sign in.
Addresses an issue that might cause apps that use the custom text wrapping function to stop working in certain scenarios.
Addresses an issue with Start menu apps and tiles in virtual desktop infrastructure (VDI) environments. The issue occurs after you sign in to the VDI environment a second time and use a Remote Desktop User Profile Disk in a non-persistent virtual desktop pool.
Addresses an issue that generates an error when printing to a document repository.
Addresses an issue that prevents Visual Basic 6.0 (VB6) applications from using ListView in MSCOMCTL.OCX after upgrading to Windows 10, version 1903 and later.
Addresses a runtime error that causes VB6 to stop working when duplicate windows messages are sent to WindowProc().
Addresses an issue that causes a stop error when the initialization of the graphics adapter fails.
Addresses an issue to reduce the likelihood of missing fonts.
Addresses an issue that prevents users from reducing the size of a window in some cases.
Addresses an issue that causes the touch keyboard to close when you touch any key.
Addresses an issue that adds an unwanted keyboard layout as the default after an upgrade or migration even if you have already removed the layout.
Addresses an issue the prevents applications from closing even though programming code directs them to close.
Addresses an issue that causes attempts to take a screenshot of a window using the PrintWindow API to fail.
Addresses an issue with a memory leak in ctfmon.exe that occurs when you refresh an application that has an editable box.
Addresses an issue that truncates a potential list of characters (candidates) when you type characters in the Simplified Chinese (Pinyin) input method editor (IME). When this happens, Chinese characters do not appear.
Addresses an issue that prevents the first key stroke from being recognized correctly in the DataGridView cell.
Addresses an issue that causes an application that uses msctf.dll to stop working, and the 0xc0000005 (Access violation) exception appears.
Addresses an issue with Dynamic Data Exchange (DDE) that causes a memory leak when multiple clients connect to the same server.
Addresses an issue that prevents Cortana Smart lighting from working as expected if you shut down the machine while Fast Shutdown is enabled.
Provides the ability for Dolby Atmos for Headphones and DTS Headphone: X to be used in 24-bit mode on devices that support 24-bit audio.
Addresses an issue that prevents the IME user dictionary from being used when leveraging folder redirection with user profiles.
Addresses an issue that causes Microsoft Office applications to close unexpectedly when using a Korean IME.
Addresses an issue that displays incorrect folder properties in File Explorer when the path is longer than MAX_PATH.
Addresses an issue with a blurry sign in screen.
Addresses an issue with Windows Update becoming unresponsive when checking for updates.
Addresses an issue that prevents the correct lock screen from appearing when the following policies are set:
- Policy "Interactive Logon: Do not require Ctrl+Alt+Del" set to "Disabled"
- HKLM\SOFRWARE\Policies\Microsoft\Windows\System
- DisableLockScreenAppNotifications = 1
- DisableLogonBackgroundImage = 1
Addresses an issue that causes File Explorer to stop working when you browse directories of raw images and other file types.
Improves the tablet experience for convertible or hybrid devices in docked scenarios.
Improves the user experience of the Windows Hello enrollment pages for face and fingerprint setup.
Prevents accounts from a different tenant from signing in to a Surface Hub device.
Updates time zone information for the Yukon, Canada.
Addresses stop error 0xC2 in usbccgp.sys.
Addresses an issue that causes the Event Viewer Microsoft Management Console (MMC) to stop working when the secondary monitor is above the primary monitor. An out of bounds exception appears.
Addresses an issue that prevents the migration of the Windows Remote Management (WinRM) service startup type.
Addresses an issue with object performance counters.
Addresses an issue that prevents Microsoft User Experience Virtualization (UE-V) settings from roaming to enable the signature files that are used for new messages, forwarded messages, and replies.
Addresses an issue that prevents users from setting the REG_EXPAND_SZ keys in some automated scenarios.
Addresses an issue with the EnhancedAppLayerSecurity node in modern device management (MDM) that prevents its setting from being applied correctly to client devices.
Addresses an issue that causes a memory leak in the LsaIso.exe process when the server is under a heavy authentication load and Credential Guard is enabled.
Addresses an issue that might cause a delay of up to two minutes when signing in or unlocking a session on Hybrid Azure Active Directory-joined machines.
Addresses an issue that prevents hash signing from working correctly when using the Microsoft Platform Crypto Provider for Trusted Platform Modules (TPM). This issue might also affect networking software, such as virtual private network (VPN) applications.
Addresses an issue that continues to display the previous username hint in the smart card sign in box after a different user has used the machine with domain credentials.
Addresses an issue that causes communication with the TPM to time out and fail.
Addresses an issue that sometimes prevents AppLocker from running an application whose publisher rule allows it to run.
Addresses an issue in which AppLocker publisher rules might sometimes prevent applications from loading software modules; this can cause partial application failure.
Addresses an issue that causes the promotion of a server to a domain controller to fail. This occurs when the Local Security Authority Subsystem Service (LSASS) process is set as Protected Process Light (PPL).
Addresses an issue that prevents you from unlocking a device if you typed a space before the username when you first signed in to the device.
Addresses an issue that causes a system to stop working and generates a 7E stop code.
Addresses an issue that causes applications to take a long time to open.
Addresses classification failures caused by the wrong User Principal Name (UPN).
Addresses an issue in cluster scenarios that causes handles to .vmcx and .vmrs files to become invalid after storage failover. As a result, live migration and other virtual machine (VM) maintenance activities fail with STATUS_UNEXPECTED_NETWORK_ERROR.
Addresses an issue with interrupt targeting that might cause an interrupt to arrive at an incorrect processor.
Addresses an issue that causes delays during shutdown when running the Microsoft Keyboard Filter Service.
Addresses an issue that causes a machine to request a new IP address after authentication.
Addresses an issue that causes the Background Intelligent Transfer Service (BITS) to download data while a device is in cellular mode without explicit user permission.
Addresses an issue that prevents Always On VPN (AOVPN) from automatically reconnecting when resuming from Sleep or Hibernate.
Addresses an issue that causes AOVPN user tunnels to use an incorrect certificate.
Addresses an issue with AOVPN that occurs when user and device tunnels are configured to connect to the same endpoint.
Addresses an issue that causes VPN apps to stop working in some cases when they attempt to enumerate VPN profiles.
Addresses an issue that causes the Optimize Drives dialog to incorrectly report that previously optimized drives need to be optimized again.
Addresses an issue that fails to turn off the host memory buffer (HMB) when you force the shutdown of a device. As a result, solid-state drives (SSDs) do not delete HMB contents.
Addresses an issue that prevents modern applications from opening because of a race condition during automatic updates. As a result, the appx package has a reduced or zero byte file size.
Addresses an issue that might cause a stop error (0xC00002E3) at startup. This issue occurs after installing certain Windows Updates that were released on or after April 21, 2020.
Addresses an issue that might cause stop error 7E in nfssvr.sys on servers running the Network File System (NFS) service.
Addresses an issue with Server Message Block (SMB). This issue incorrectly logs the Microsoft-Windows-SMBClient 31013 event in the Microsoft-Windows-SMBClient/Security event log of an SMB client when an SMB server returns STATUS_USER_SESSION_DELETED. This issue occurs when SMB client users or applications open multiple SMB sessions using the same set of Transmission Control Protocol (TCP) connections on the same SMB Server. This issue most likely occurs on Remote Desktop Servers.
Addresses an issue that causes SMB to incorrectly use the original, cached non-Continuous Available handle to a file. This handle becomes invalid after a network error or storage failover. As a result, applications fail with errors such as STATUS_UNEXPECTED_NETWORK_ERROR.
Addresses an issue that causes the loss of written data when an application opens a file and writes to the end of the file in a share folder.
Addresses an issue with some apps, such as Microsoft Excel, that occurs when using the Microsoft Input Method Editor (IME) for Chinese and Japanese languages. You might receive an error, or the app might stop responding or close when you attempt to drag using the mouse.
Addresses an issue that causes Windows Defender Firewall components to deadlock. This might cause the system to stop responding or cause sign in or sign out to stop responding.

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
Users of the Microsoft Input Method Editor (IME) for Japanese or Chinese languages might experience issues when attempting various tasks. You might have issues with input, receive unexpected results, or might not be able to enter text.	All IME issues listed in KB4564002 were resolved in KB4586853.

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 general information about SSUs, see Servicing stack updates and Servicing Stack Updates (SSU): Frequently Asked Questions.

If you are using Windows Update, the latest SSU (KB4570334) 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

Release Channel	Available	Next Step
Windows Update or Microsoft Update	Yes	Go to Settings > Update & Security > Windows Update. In the Optional updates available area, you’ll find the link to download and install the update.
Microsoft Update Catalog	Yes	To get the standalone package for this update, go to the Microsoft Update Catalog website.
Windows Server Update Services (WSUS)	No	You can import this update into WSUS manually. See the Microsoft Update Catalog for instructions.

File information

For a list of the files that are provided in this update, download the file information for cumulative update 4571744.

September 3, 2020—KB4571744 (OS Build 19041.488) Preview

Highlights

Improvements and fixes

Known issues in this update

How to get this update

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