October 13, 2020—KB4580346 (OS Build 14393.3986) - EXPIRED

^{NEW 8/5/21} EXPIRATION NOTICE

IMPORTANT As of 8/5/2021, this KB is no longer available from Windows Update, the Microsoft Update Catalog, or other release channels. We recommend that you update your devices to the latest security quality update.

^{NEW 10/13/20} IMPORTANT Release notes are changing! To learn about the new URL, metadata updates, and more, see What’s next for Windows release notes.

^{UPDATED 10/28/20} IMPORTANT Windows 10 Enterprise, version 1607 stopped receiving updates after 4/9/2019. Windows 10 2016 LTSB will continue to have only cumulative monthly security updates (known as the “B” or “Update Tuesday” release) until 10/13/2026. Non-security releases (known as “C” releases) for this operating system ended in July 2020.

^{UPDATED 10/28/20} 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. To view other notes and messages, see the Windows 10, version 1607 update history home page.

Highlights

Adds a notification to Internet Explorer 11 that informs users about the end of support for Adobe Flash in December 2020. For more information, see KB4581051.
Updates 2021 time zone information for Fiji.
Updates to improve security when Windows performs basic operations.
Updates for storing and managing files.

Improvements and fixes

This security update includes quality improvements. Key changes include:

Provides the ability to sync the Microsoft Edge IE Mode unidirectional session cookie when an administrator configures the session cookie.
Adds a notification to Internet Explorer 11 that informs users about the end of support for Adobe Flash in December 2020. For more information, see KB4581051.
Addresses an issue with Microsoft Edge IE Mode that occurs when you enable Configure enhanced hang detection for Internet Explorer mode in Microsoft Edge.
Addresses an issue that causes apps that use Dynamic Data Exchange (DDE) to stop responding when you attempt to close the app.
Updates 2021 time zone information for Fiji.
Addresses an issue with creating HTML reports using tracerpt.
Addresses an issue with the Group Policy service that might recursively delete critical files in alphabetic order from %systemroot%\system32. This issue occurs when a policy has been configured to delete cached profiles. These file deletions might cause stop error “0x5A (CRITICAL_SERVICE_FAILED)” boot failures.
Addresses an issue that causes Windows to stop working and generates error 0x17. This issue occurs when Windows Defender Device Guard is enabled, and a driver is loaded with a 4K Microsoft Portable Executable (PE) header.
Addresses an issue with creating null ports using the user interface.
Addresses an issue that might prevent you from accessing the Security Options data view in the Group Policy Management Editor (gpedit.msc) or Local Security Policy Editor (secpol.msc). The error is, "MMC has detected an error in a snap-in”.
Security updates to Windows App Platform and Frameworks, Windows Fundamentals, Windows Virtualization, Windows Kernel, and Windows Storage and Filesystems.

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 Security Update Guide.

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

After installing KB4467684, the cluster service may fail to start with the error “2245 (NERR_PasswordTooShort)” if the group policy “Minimum Password Length” is configured with greater than 14 characters.

For this update and all the updates before or after this update, this issue is resolved in KB4601318.

When installing a third-party driver, you might receive the error, “Windows can’t verify the publisher of this driver software”. You might also see the error, “No signature was present in the subject” when attempting to view the signature properties using Windows Explorer.

This issue occurs when one or more of the following is present in a driver package:

An improperly formatted catalog file is identified during validation by Windows. Starting with this release, Windows will require the validity of DER encoded PKCS#7 content in catalog files. Catalogs files must be signed per section 11.6 of describing DER-encoding for SET OF members in X.690.
A driver catalog file extension is not one of supported extensions.

If this happens you should contact the driver vendor or device manufacturer (OEM) and ask them for an updated driver to correct the issue.

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 and applying Microsoft security fixes. 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 (KB4576750) 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 and Microsoft Update	Yes	None. This update will be downloaded and installed automatically from Windows 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)	Yes	This update will automatically sync with WSUS if you configure Products and Classifications as follows: Product: Windows 10 Classification: Security Updates

File information

For a list of the files that are provided in this update, download the file information for cumulative update 4580346.

October 13, 2020—KB4580346 (OS Build 14393.3986) - EXPIRED

Highlights

Improvements and fixes

Known issues in this update

How to get this update

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