Windows 10 21H1 (May 2021 Update) is the eleventh update refresh since the original release and the first semi-annual feature update of 2021, which Microsoft is starting to roll out on May 18, 2021, with fixes and a small set of features.
Microsoft typically rolls out two feature updates each year. The one in the spring is usually considered the more significant release with new features, improvements, and visual changes. At the same time, the one in the fall is a smaller update designed to complement the previous release without anything significant.
In 2021, the company is changing the approach to continue updating Windows 10, making the first update the minor release to ensure that engineers have more time to work on the second feature update and Windows 11.
Windows 10 version 21H1 is an optional update available for devices running versions 2004 and 20H2. However, the company is initially limiting the availability and placing safeguard holds to prevent potential problems for not yet fully compatible devices. When the new version becomes available for your device, you will receive a “Feature update to Windows 10, version 21H1” notification to download it manually through Windows Update.
If you are a “seeker,” you may force the upgrade by clicking the Check for updates button in the Windows Update settings and then clicking the Download and install button. Alternatively, you can install the May 2021 Update using the Media Creation Tool to perform a clean install or in-place upgrade. Or you will also be able to use the Update Assistant or download the ISO file to create a USB bootable media to proceed with the upgrade.
In this guide, we will highlight the new features and improvements available with Windows 10 version 21H1.
Windows 10 21H1 new features
- New Windows Hello multi-camera feature.
- News and interests widget for Windows 10 21H1 taskbar.
- Windows Mixed Reality new feature to set the sleep timer for headsets.
- Windows Defender Application Guard (WDAG) improvements.
- Windows Management Instrumentation (WMI) Group Policy Service (GPSVC) improvements.
- New Microsoft Edge (Chromium) support for kiosk mode on Windows 10 May 2021 Update.
- WinHTTP Web Proxy Auto-Discovery Service improvements.
- Updates the Open Mobile Alliance (OMA) Device Management (DM) sync protocol.
- Windows 10 startup times for apps with roaming settings improvements on version 21H1.
- Windows Server Storage Migration Service new feature to migrate from NetApp FAS arrays to Windows Servers and clusters.
What’s new on Windows 10 May 2021 Update
As part of the new features, version 21H1 (May 2021 Update) won’t significantly change the way you use Windows 10. Instead, it will focus on some key areas, including quality, remote access, and security.
For example, if you use Windows Hello for biometric authentication, the new multi-camera support will help you set another camera the default when using high-end displays that include integrated webcams.
This new release fixes a delay problem on Windows Defender Application Guard (WDAG) when opening a Microsoft Office. It improves file copying for files over 400MB in size when using the Robocopy command-line tool. And it addresses a problem that causes high usage of system memory when the WDAG container is idle.
Windows 10 21H1 also introduces better support for remote work scenarios using Windows Management Instrumentation (WMI) Group Policy Service (GPSVC). Also, it fixes slow membership propagation when editing a user or computer group in Active Directory (AD).
Also, Microsoft is bringing the news and interests widget to the taskbar. The idea of the feature is to keep you engaged on your computer instead of opening your phone to peek into news and other information throughout the day.
The widget was originally planned for version 21H2, but the company is making it available with the first feature update of 2021.
If you use Windows Mixed Reality with the May 2021 Update, you will find a new option to adjust the amount of idle time before a headset goes to sleep in the Settings app.
And for commercial customers, the Windows Server Storage Migration Service brings a couple of improvements, including new support for migration from NetApp FAS arrays to Windows Servers and clusters. It resolves multiple issues and improves reliability.
Changes and improvements
In addition to the small set features, this minor update includes some under the hood tweaks, including:
- New support for using the new Chromium-based Microsoft Edge as the assigned access single kiosk app.
- Improves startup times for applications with roaming settings when User Experience Virtualization (UE-V) is turned on.
- Updates the Open Mobile Alliance (OMA) Device Management (DM) sync protocol by adding a check-in reason for requests from the client to the server. The check-in reason will allow the mobile device management (MDM) service to make better decisions about sync sessions. The OMA-DM service must negotiate a protocol version of 4.0 with the Windows OMA-DM client with this change.
- Turns off token binding by default in Windows Internet (WinINet).
- New dfslogkey in
HKEY_LOCAL_MACHINE/SOFTWARE/MICROSOFT/dfslog. The RootShareAcquireSuccessEvent field has the following possible values, including a default value of 1 to enable the log and a value other than 1 disables the log. - Improves the ability of the WinHTTP Web Proxy Auto-Discovery Service to ignore invalid Web Proxy Auto-Discovery Protocol (WPAD) URLs that the Dynamic Host Configuration Protocol (DHCP) server returns.
- Enhances data loss prevention and insider risk management solution functionalities in Microsoft 365 endpoints.
Feature update fixes
These are the latest fixes available with the Windows 10 May 2021 Update (version 21H1):
- Fixed an issue that prevents a site from transitioning out of Microsoft Edge IE Mode when expected.
- Addressed a problem that fails to remove mandatory profiles completely when you sign out using the “Delete cached copies of roaming profiles” Group Policy.
- Fixed an issue that causes blank tiles to appear on the Start menu with names such as “ms-resource:AppName” or “ms-resource:appDisplayName.”
- Addressed a problem with the Microsoft Japanese Input Method Editor (IME) that prevents an app’s custom candidate window from displaying correctly.
- Fixed an issue that occurs when you install inventory applications.
- Addressed a problem that includes kernel-mode rules for .NET applications in Windows Defender Application Control policies. As a result, the generated policies are significantly larger than necessary.
- Fixed an issue that causes devices to fail Device Health Attestation.
- Addressed a problem that turns off S Mode when you enable System Guard Secure Launch on a system running Windows 10 in S Mode.
- Fixed an issue that causes “lsass.exe” memory usage to grow until the system becomes unusable.
- Addressed a problem with a race condition between Task Scheduler and the Workstation Service.
- Fixed an issue that causes Azure Active Directory authentication to fail after signing in on Windows Virtual Desktop machines.
- Addressed a problem that causes AAD Work Accounts to unexpectedly disappear from certain apps such as Microsoft Teams or Microsoft Office.
- Fixed an issue with a partial Service Connection Point (SCP) configuration that causes dsregcmd.exe to stop working.
- Addressed a problem that accidentally triggers hybrid AAD joining when the Group Policy “Register domain-joined computers as devices” is set to DISABLED.
- Fixed an issue that might generate a stop error when Docker containers run with process isolation.
- Addressed a problem that causes automatic enrollment and certificate retrieval to fail with the error, “The parameter is incorrect.”
- Fixed an issue that might cause Microsoft Defender Application Guard virtual machines to stop responding when Microsoft Defender Application Guard for Office opens a document.
- Addressed a problem that prevents some media players from playing content on hybrid devices running with dGPU on iGPU displays.
- Fixed an issue with race conditions that cause high CPU usage.
- Addressed a problem with a deadlock in the New Technology File System (NTFS).
- Fixed an issue that causes DWM.exe to stop working in some cases.
- Addressed a problem that might prevent an application screen from working when using a Remote Desktop ActiveX control embedded in an HTML page.
- Fixes an issue causing 0xC2 (BAD_POOL_CALLER) bug check when using IOCTL_SCSI_PASS_THROUGH_DIRECT.
Although these changes, improvements, and fixes are part of the 21H1 update development, Microsoft is also making them available ahead of the feature update release for version 20H2.
Editor’s note: This guide includes features and improvements that appeared until Windows 10 build 19043.964. It should be noted that this guide focuses on features for consumers, as Microsoft may also be adding other features aimed at enterprises, which won’t be included here. (Last updated on May 2021.)
Mauro Huculak is a Windows expert and the Editor-in-Chief who started Pureinfotech in 2010 as an independent online publication. He is also been a Windows Central contributor for nearly a decade. Mauro has over 12 years of experience writing comprehensive guides and creating professional videos about Windows, software, and related technologies, including Android and Linux. Before becoming a technology writer, he was an IT administrator for seven years. In total, Mauro has over 20 years of combined experience in technology. Throughout his career, he achieved different professional certifications from Microsoft (MSCA), Cisco (CCNP), VMware (VCP), and CompTIA (A+ and Network+), and he has been recognized as a Microsoft MVP for many years. You can follow him on X (Twitter), YouTube, LinkedIn and About.me.