April 14, 2020—KB4549951 (OS Builds 18362.778 and 18363.778) - EXPIRED

NEW 8/5/21
EXPIRATION NOTICE****IMPORTANTAs 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
IMPORTANTWe have been evaluating the public health situation, and we understand this is impacting our customers. In response to these challenges, we are prioritizing our focus on security updates. Starting in May 2020, we are pausing all optional non-security releases (C and D updates) for all the supported versions of Windows client and server products (Windows 10, version 1909 down to Windows Server 2008 SP2).There is no change to the monthly security updates (B release – Update Tuesday); these will continue as planned to ensure business continuity and to keep our customers protected and productive.

What’s new for Windows 10, version 1909 and Windows 10, version 1903 release notesWindows 10, versions 1903 and 1909 share a common core operating system and an identical set of system files. As a result, the new features in Windows 10, version 1909 were included in the recent monthly quality update for Windows 10, version 1903 (released October 8, 2019), but are currently in a dormant state. These new features will remain dormant until they are turned on using an enablement package, which is a small, quick-to-install “master switch” that simply activates the Windows 10, version 1909 features.To reflect this change, the release notes for Windows 10, version 1903 and Windows 10, version 1909 will share an update history page. Each release page will contain a list of addressed issues for both 1903 and 1909 versions. Note that the 1909 version will always contain the fixes for 1903; however, 1903 will not contain the fixes for 1909. This page will provide you with the build numbers for both 1909 and 1903 versions so that it will be easier for support to assist you if you encounter issues.For more details about the enablement package and how to get the feature update, see the Windows 10, version 1909 delivery options blog.

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

Highlights

• Updates to improve security when using Microsoft Office products.
• Updates to improve security when Windows performs basic operations.
• Updates for storing and managing files.

Improvements and fixes

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Windows 10, version 1909

This security update includes quality improvements. Key changes include:

• This build includes all the improvements from Windows 10, version 1903.
• No additional issues were documented for this release.

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Windows 10, version 1903

NoteThis release also contains updates for Microsoft HoloLens (OS Build 18362.1057) released April 14, 2020. 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.

This security update includes quality improvements. Key changes include:

• Addresses an issue that prevents certain apps from installing if they are published using a Group Policy Object.

• Addresses an issue that prevents a wired network interface from obtaining a new Dynamic Host Configuration Protocol (DHCP) IP address on new subnets and virtual LANs (VLAN) after wired 802.1x re-authentication. The issue occurs if you use VLANs that are based on accounts and a VLAN change occurs after a user signs in.

• Security updates to the Microsoft Scripting Engine, Windows App Platform and Frameworks, Windows Cloud Infrastructure, Windows Virtualization, Microsoft Graphics Component, Windows Kernel, Windows Media, Windows Shell, Windows Management, Windows Fundamentals, Windows Virtualization, Windows Storage and Filesystems, Windows Update Stack, and the Microsoft JET Database Engine .

• 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 ImprovementsMicrosoft 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 updateSymptom	Workaround
We have seen social media reports related to KB4549951 that mention Bluetooth, a stop error with a blue screen, and other related issues.	To date, we have not seen these issues reflected in telemetry, support data, or customer feedback channels. We continuously investigate all customer feedback and are closely monitoring this situation.NoteIf you experience any issues, we’d like to know. Please provide feedback using the keyboard shortcut Windows + For go to the Startmenu and select Feedback Hubso that we can investigate.
After installing this update on a Windows 10 device with a wireless wide area network (WWAN) LTE modem, reaching the internet might not be possible. However, the Network Connectivity Status Indicator (NCSI) in the notification area might still indicate that you are connected to the internet.	This issue is resolved in KB4559004.
How to get this updateBefore installing this updateMicrosoft 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 (KB4552152) 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
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Windows Update and Microsoft Update	Yes
Microsoft Update Catalog	Yes
Windows Server Update Services (WSUS)	Yes