September 14, 2021—KB5005566 (OS Build 18363.1801)

EXPIRATION NOTICE

As of 9/12/2023, KB5005566 is only available from Windows Update. This update is no longer available from the Microsoft Update Catalog, or other release channels. We recommend that you update your devices to the latest security quality update.

^8/24/2021 IMPORTANT Starting in October 2021, there will no longer be optional, non-security releases (known as "C" releases) for Windows 10, version 1909. Only cumulative monthly security updates (known as the "B" or Update Tuesday release) will continue for Windows 10, version 1909.

^11/19/20 For information about Windows update terminology, see the article about the types of Windows updates and the monthly quality update types. To view other notes and messages, see the Windows 10, version 1909 update history home page.

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

Highlights

Updates security for your Windows operating system.

Improvements and fixes

This security update includes quality improvements. Key changes include:

Addresses an issue that causes PowerShell to create an infinite number of child directories. This issue occurs when you use the PowerShell Move-Item command to move a directory to one of its children. As a result, the volume fills up and the system stops responding.

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

For more information about the resolved security vulnerabilities, please refer to the new Security Update Guide website.

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.

Windows 10 servicing stack update - 18363.1790

This update makes quality improvements to the servicing stack, which is the component that installs Windows updates. Servicing stack updates (SSU) ensure that you have a robust and reliable servicing stack so that your devices can receive and install Microsoft updates.

Known issues in this update

Symptom	Workaround
After installing this update, devices which attempt to connect to a network printer for the first time might fail to download and install the necessary printer drivers. Devices which had connected to and installed the printer prior to the installation of KB5005566 are unaffected and operations to that printer will succeed as usual. This issue has been observed in devices which access printers via a print server using HTTP connections. When a client connects to the server to install the printer, a directory mismatch occurs, which causes the installer files to generate incorrectly. As a result, the drivers may not download. Note The printer connection methods described in this issue are not commonly used by devices designed for home use. Printing environments affected by this issue are more commonly found in enterprises and organizations.	This issue is resolved in KB5005624.
After installing this or a later update, installation of printers using Internet Printing Protocol (IPP) might not complete successfully. Devices which had connected to and installed the printer prior to the installation of KB5005566 are unaffected and print operations to that printer will succeed as usual. Note IPP is not commonly used by devices designed for home use. The printing environments affected by this issue are more commonly found in enterprises and organizations.	This issue is resolved in KB5007189.
After installing this update, you might receive a prompt for administrative credentials every time you attempt to print in environments in which the print server and print client are in different times zones. Note The affected environments described in this issue are not commonly used by devices designed for home use. The printing environments affected by this issue are more commonly found in enterprises and organizations.	This issue is resolved in KB5006667.

Symptom

Workaround

After installing this update, devices which attempt to connect to a network printer for the first time might fail to download and install the necessary printer drivers. Devices which had connected to and installed the printer prior to the installation of KB5005566 are unaffected and operations to that printer will succeed as usual.

This issue has been observed in devices which access printers via a print server using HTTP connections. When a client connects to the server to install the printer, a directory mismatch occurs, which causes the installer files to generate incorrectly. As a result, the drivers may not download.

Note The printer connection methods described in this issue are not commonly used by devices designed for home use. Printing environments affected by this issue are more commonly found in enterprises and organizations.

This issue is resolved in KB5005624.

After installing this or a later update, installation of printers using Internet Printing Protocol (IPP) might not complete successfully. Devices which had connected to and installed the printer prior to the installation of KB5005566 are unaffected and print operations to that printer will succeed as usual.

Note IPP is not commonly used by devices designed for home use. The printing environments affected by this issue are more commonly found in enterprises and organizations.

This issue is resolved in KB5007189.

After installing this update, you might receive a prompt for administrative credentials every time you attempt to print in environments in which the print server and print client are in different times zones.

Note The affected environments described in this issue are not commonly used by devices designed for home use. The printing environments affected by this issue are more commonly found in enterprises and organizations.

This issue is resolved in KB5006667.

How to get this update

Before installing this update

Microsoft now combines the latest servicing stack update (SSU) for your operating system with 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.

Prerequisite:

You must install the July 13, 2021 SSU (KB5004748) before installing the LCU.

Install this update

Release Channel	Available	Next Step
Windows Update and Microsoft Update	Yes	None. This update will be downloaded and installed automatically from Windows Update.
Windows Update for Business	No	No longer available.
Microsoft Update Catalog	No	No longer available.
Windows Server Update Services (WSUS)	No	No longer available.

If you want to remove the LCU

To remove the LCU after installing the combined SSU and LCU package, use the DISM/Remove-Package command line option with the LCU package name as the argument. You can find the package name by using this command: DISM /online /get-packages.

Running Windows Update Standalone Installer (wusa.exe) with the /uninstall switch on the combined package will not work because the combined package contains the SSU. You cannot remove the SSU from the system after installation.

File information

For a list of the files that are provided in this update, download the file information for cumulative update 5005566.

For a list of the files that are provided in the servicing stack update, download the file information for the SSU - version 18363.1790.

September 14, 2021—KB5005566 (OS Build 18363.1801)

Highlights

Improvements and fixes

Windows 10 servicing stack update - 18363.1790

Known issues in this update

How to get this update

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