October 8, 2019—KB4519338 (OS Build 17763.805)

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Starting with update KB4497934, we are introducing functionality that allows you to decide when to install a feature update. You control when you get a feature update while simultaneously keeping your devices up to date. Feature updates that are available for eligible devices will appear in a separate module on the Windows Update page (Settings > Update & Security > Windows Update). If you would like to get an available update right away, select Download and install now. To find out more about this feature, please go to this blog.

When Windows 10 devices are at, or within several months of reaching, end of service, Windows Update will begin to automatically initiate a feature update. This keeps those devices supported and receiving the monthly updates that are critical to device security and ecosystem health.

Note This release also contains updates for Microsoft HoloLens (OS Build 17763.806) released October 8, 2019. Microsoft will release an update directly to the Windows Update Client to improve Windows Update reliability on Microsoft HoloLens that have not updated to this most recent OS Build.

ePub support ending in Microsoft Edge

Microsoft Edge will end support for e-books that use the .epub file extension over the next several months. For more information, see Download an ePub app to keep reading e-books.

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.

Highlights

Updates to improve security when using Internet Explorer and Microsoft Edge.
Updates for verifying user names and passwords.

Improvements and fixes

This security update includes quality improvements. Key changes include:

Addresses an issue in the Keyboard Lockdown Subsystem that may not filter key input correctly.
Addresses an issue in security bulletin CVE-2019-1318 that may cause client or server computers that don’t support Extended Master Secret (EMS) RFC 7627 to have increased connection latency and CPU utilization. This issue occurs while performing full Transport Layer Security (TLS) handshakes from devices that don’t support EMS, especially on servers. EMS support has been available for all the supported versions of Windows since calendar year 2015 and is being incrementally enforced by the installation of the October 8, 2019 and later monthly updates.
Addresses an issue with applications and printer drivers that utilize the Windows JavaScript engine (jscript.dll) for processing print jobs.
Security updates to Windows Shell, Internet Explorer, Microsoft Scripting Engine, Microsoft Edge, Windows App Platform and Frameworks, Windows Cryptography, Windows Authentication, Windows Kernel, and Windows Server.

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
Certain operations, such as rename, that you perform on files or folders that are on a Cluster Shared Volume (CSV) may fail with the error, “STATUS_BAD_IMPERSONATION_LEVEL (0xC00000A5)”. This occurs when you perform the operation on a CSV owner node from a process that doesn’t have administrator privilege.	Do one of the following: Perform the operation from a process that has administrator privilege. Perform the operation from a node that doesn’t have CSV ownership. Microsoft is working on a resolution and will provide an update in an upcoming release.
After installing KB4493509, devices with some Asian language packs installed may receive the error, "0x800f0982 - PSFX_E_MATCHING_COMPONENT_NOT_FOUND."	Uninstall and reinstall any recently added language packs. For instructions, see Manage the input and display language settings in Windows 10. Select Check for Updates and install the April 2019 Cumulative Update. For instructions, see Update Windows 10. Note If reinstalling the language pack does not mitigate the issue, reset your PC as follows: Go to the Settings app > Recovery. Select Get Started under the Reset this PC recovery option. Select Keep my Files. Microsoft is working on a resolution and will provide an update in an upcoming release.
We are investigating reports that a small number of devices may startup to a black screen during the first logon after installing updates.	This issue is resolved in KB4520062.
After installing this update, Windows Mixed Reality Portal users may intermittently receive a “15-5” error code. In some cases, Windows Mixed Reality Portal may report that the headset is sleeping and pressing “Wake up” may appear to produce no action.	This issue is resolved in KB4520062.
When setting up a new Windows device during the Out of Box Experience (OOBE), you might be unable to create a local user when using Input Method Editor (IME). This issue might affect you if you are using the IME for Chinese, Japanese, or Korean languages. Note This issue does not affect using a Microsoft Account during OOBE.	This issue is resolved in KB4534321.
Updates for Windows released October 8, 2019 or later provide protections, tracked by CVE-2019-1318, against an attack that could allow unauthorized access to information or data within TLS connections. This type of attack is known as a man-in-the-middle exploit. Windows might fail to connect to TLS clients and servers that do not support Extended Master Secret for resumption (RFC 7627). Lack of RFC support might cause one or more of the following errors or logged events: "The request was aborted: Could not create SSL/TLS secure Channel" SCHANNEL event 36887 is logged in the System event log with the description, "A fatal alert was received from the remote endpoint. The TLS protocol defined fatal alert code is 20."	For information, see KB4528489.

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 more information, see Servicing stack updates.

If you are using Windows Update, the latest SSU (KB4521862) 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 synchronize 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 4519338.

October 8, 2019—KB4519338 (OS Build 17763.805)

Highlights

Improvements and fixes

Known issues in this update

How to get this update

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