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Windows 10 21H2

Windows 10 Enterprise LTSC 2021

Every published release for Windows 10 Enterprise LTSC 2021, newest first: what each update changes, whether to install it and any confirmed known issues.

Latest
KB5136493 Nov 13, 2026
Build
19044.7850
Released
Nov 16, 2021
Enterprise LTSC
updates until Jan 12, 2027
IoT Enterprise LTSC
updates until Jan 13, 2032
Known issues
14 open

Build history

  • Windows 10 21H2 / 22H2 Windows 10 21H2 / 22H2 Out-of-band update
    Out-of-band

    KB5061979

    Hyper-V fix stops confidential VMs from hanging or restarting

    Fixes an issue that could make confidential virtual machines on Hyper-V stop responding or restart unexpectedly, affecting service availability. CJK text can still look blurry in some browsers at 96 DPI.

    Check the newer update, KB5058481
    Windows 10 support ended on October 14, 2025. Microsoft no longer provides free Windows Update updates, technical assistance, or security fixes.
    Known issues: 1 open
    • Noto fonts

    Key changes 4 changes

    • Improved Windows 10, version 22H2: This version includes the improvements listed for supported Windows 10, version 21H2 editions.
    • Improved Servicing stack: The component that installs Windows updates receives quality improvements.
    • Fix Hyper-V Platform: Confidential virtual machines could stop responding or restart unexpectedly, disrupting service and requiring manual intervention. Azur...

    Read update Source: Microsoft

    Builds
    19044.5859 · 19045.5859
    Restart
    Required
  • Windows 10 21H2 / 22H2 Windows 10 21H2 / 22H2 Out-of-band update
    Out-of-band

    KB5061768

    LSASS and BitLocker recovery issue fixed

    Fixes an issue that could crash LSASS and send some Intel vPro PCs into BitLocker recovery. Blurry CJK text at 96 DPI remains a known issue.

    Check the newer update, KB5061979
    Windows 10 support ended October 14, 2025. Microsoft recommends moving to Windows 11; after that date, Windows 10 no longer receives free updates, technical assistance, or security fixes.
    Known issues: 1 open
    • Noto fonts

    Key changes 3 changes

    • Improved Servicing stack: The component that installs Windows updates receives quality improvements.
    • Fix OS Security (Known Issue): The issue that could stop LSASS and trigger Automatic Repair with a BitLocker recovery prompt is fixed for the listed Intel vPro device...
    • Fix OS Security (Known Issue): The issue that could stop LSASS and trigger Automatic Repair with a BitLocker recovery prompt is fixed for the listed Intel vPro device...

    Read update Source: Microsoft

    Builds
    19044.5856 · 19045.5856
    Restart
    Required
  • Windows 10 21H2 / 22H2 Windows 10 21H2 / 22H2 Security update
    Zero-day

    KB5058379

    Exploited scripting and Windows privilege flaws patched

    The update fixes 36 vulnerabilities, including five that attackers are already exploiting. It also improves Linux-system detection and servicing, but the update is no longer available.

    Windows 10 support ended on October 14, 2025. Microsoft no longer provides free updates, technical assistance, or security fixes through Windows Update.
    Known issues: 2 open
    • Noto fonts
    • Citrix

    Key changes 36 CVEs · 3 changes

    • Improved Secure Boot Advanced Targeting (SBAT) and Linux Extensible Firmware Interface (EFI): Detection of Linux systems is improved.
    • Improved Windows 10, version 22H2: The 22H2 build includes the improvements listed for the supported 21H2 editions; no additional issues are documented for this release.
    • Improved Servicing stack: The component that installs Windows updates receives quality improvements.

    Read update Source: Microsoft

    Builds
    19044.5854 · 19045.5854
    Security
    36 fixed · 3 critical · 5 exploited
  • Windows 10 21H2 / 22H2 Windows 10 21H2 / 22H2 Security update
    Zero-day

    KB5055518

    Exploited log file driver flaw fixed; Hello sign-in tightened

    Attackers are exploiting a Windows Common Log File System Driver flaw to gain higher privileges. The update also changes Windows Hello face sign-in and other security protections.

    Windows 10 support ended on October 14, 2025.
    Known issues: 3 open
    • Citrix
    • Noto fonts issue
    • System Guard Runtime Monitor Broker service

    Key changes 62 CVEs · 5 changes

    • New OS Security: A new folder appears on the system drive for added protection. Do not delete it; no action is needed.
    • Improved Windows 10, version 22H2: Version 22H2 includes the improvements listed for supported Windows 10, version 21H2 editions.
    • Improved Daylight Saving Time (DST): Devices in Chile’s Aysén region get the 2025 daylight saving time change.

    Read update Source: Microsoft

    Builds
    19044.5737 · 19045.5737
    Security
    62 fixed · 5 critical · 1 exploited
  • Windows 10 21H2 / 22H2 Windows 10 21H2 / 22H2 Security update
    Zero-day

    KB5053606

    Exploited NTFS, Fast FAT, and MMC flaws patched

    Attackers are exploiting flaws in NTFS, Fast FAT, and Microsoft Management Console; the update also covers critical Remote Desktop code-execution flaws. Windows 10 support has since ended.

    Windows 10 support ended October 14, 2025. Microsoft no longer provides free updates, technical help, or security fixes for Windows 10.
    Known issues: 4 open
    • Citrix
    • System Guard Runtime Monitor Broker service
    • and 2 more

    Key changes 30 CVEs · 3 changes

    • Improved Windows 10, version 22H2: Version 22H2 includes all improvements from supported Windows 10, version 21H2 editions.
    • Improved Windows 10, version 21H2: The update makes security improvements to internal Windows functions.
    • Improved Servicing stack: The part of Windows that installs updates gets quality improvements.

    Read update Source: Microsoft

    Builds
    19044.5608 · 19045.5608
    Security
    30 fixed · 2 critical · 5 exploited
  • Windows 10 21H2 / 22H2 Windows 10 21H2 / 22H2 Security update
    Zero-day

    KB5051974

    Exploited Storage and WinSock flaws put Windows at risk

    Attackers are exploiting flaws in Windows Storage and the WinSock ancillary function driver. An LDAP flaw also allows remote code execution; USB printer and other known issues are listed.

    As of March 31, 2026, this update is no longer available. Microsoft recommends updating devices to the latest version of Windows.
    Known issues: 4 open
    • Citrix
    • System Guard Runtime Monitor Broker service
    • and 2 more

    Key changes 32 CVEs · 3 changes

    • Improved Windows 10, version 22H2: Version 22H2 includes all improvements from supported version 21H2 editions.
    • Improved Windows 10, version 21H2: Windows gets miscellaneous security improvements to internal features.
    • Improved Servicing stack: The component that installs Windows updates gets quality improvements.

    Read update Source: Microsoft

    Builds
    19044.5487 · 19045.5487
    Security
    32 fixed · 1 critical · 2 exploited
  • Windows 10 21H2 / 22H2 Windows 10 21H2 / 22H2 Security update
    Zero-day

    KB5049981

    Exploited Hyper-V flaws fixed among 121 vulnerabilities

    Addresses 121 vulnerabilities, including five critical flaws and three exploited Hyper-V vulnerabilities. It also adds drivers to the vulnerable driver blocklist for LTSC editions.

    As of March 31, 2026, this update is no longer available through Microsoft release channels. Microsoft recommends updating devices to the latest version of Windows.

    Key changes 121 CVEs · 3 changes

    • Improved Windows 10, version 22H2: Version 22H2 includes all the improvements from supported Windows 10 version 21H2 editions.
    • Improved Windows Kernel Vulnerable Driver Blocklist file (DriverSiPolicy.p7b): The vulnerable driver blocklist includes more drivers that could be used in BYOVD attacks.
    • Improved Servicing stack: The component that installs Windows updates receives quality improvements.

    Read update Source: Microsoft

    Builds
    19044.5371 · 19045.5371
    Security
    121 fixed · 5 critical · 3 exploited
  • Windows 10 21H2 / 22H2 Windows 10 21H2 / 22H2 Security update
    Zero-day

    KB5048652

    Exploited Common Log File System flaw patched; Sysprep error fixed

    The update fixes 46 vulnerabilities, including nine critical ones and an actively exploited flaw in the Common Log File System driver. It also fixes a Sysprep error on Windows 10 Enterprise and IoT Enterprise LTSC 2021.

    As of March 31, 2026, the update is no longer available from the Microsoft Update Catalog or other release channels; Microsoft recommends updating devices to the latest version of Windows.

    Key changes 46 CVEs · 3 changes

    • Improved Windows 10, version 22H2: Includes all improvements from supported Windows 10, version 21H2 editions.
    • Improved Servicing stack: The component that installs Windows updates receives quality improvements.
    • Fix Sysprep /generalize: On Windows 10 Enterprise LTSC 2021 and IoT Enterprise LTSC 2021, Sysprep no longer fails with error 0x80073cf when you remove a package...

    Read update Source: Microsoft

    Builds
    19044.5247 · 19045.5247
    Security
    46 fixed · 9 critical · 1 exploited
  • Windows 10 21H2 / 22H2 Windows 10 21H2 / 22H2 Security update
    Zero-day

    KB5046613

    Exploited Task Scheduler flaw patched; game startup restored

    Closes 31 vulnerabilities, including two exploited flaws, and restores startup for some games and apps. The update is no longer available from Microsoft release channels.

    As of March 31, 2026, this update is no longer available from Microsoft release channels. Microsoft recommends updating devices to the latest version of Windows.

    Key changes 31 CVEs · 4 changes

    • Improved Windows Kernel Vulnerable Driver Blocklist file (DriverSiPolicy.p7b): The blocklist includes more drivers that are at risk of attacks using vulnerable drivers.
    • Improved Servicing stack: The component that installs Windows updates gets quality improvements to help devices receive and install Microsoft updates reliably.
    • Fix Some games fail to start: Some games that failed to start or stopped responding after KB5045594 can start again.

    Read update Source: Microsoft

    Builds
    19044.5131 · 19045.5131
    Security
    31 vulnerabilities fixed · 2 actively exploited
  • Windows 10 21H2 / 22H2 Windows 10 21H2 / 22H2 Security update
    Zero-day

    KB5044273

    Exploited MMC and MSHTML flaws patched

    Addresses 57 vulnerabilities, including exploited flaws in Microsoft Management Console and the MSHTML Platform. It is no longer available; several reported AVD, app-launch and OpenSSH issues were later addressed by other updates.

    As of March 31, 2026, this update is no longer available from Microsoft Update Catalog or other release channels. Microsoft recommends updating devices to the latest version of Windows.

    Key changes 57 CVEs · 3 changes

    • Improved Windows 10, version 22H2: This build includes the improvements from supported Windows 10, version 21H2 editions.
    • Improved Miscellaneous security improvements to internal OS functionality: Windows 10, version 21H2 LTSC editions receive miscellaneous security improvements to internal operating system functionality.
    • Improved Servicing stack: The component that installs Windows updates receives quality improvements.

    Read update Source: Microsoft

    Builds
    19044.5011 · 19045.5011
    Security
    57 fixed · 1 critical · 2 exploited
  • Windows 10 21H2 / 22H2 Windows 10 21H2 / 22H2 Security update
    Zero-day

    KB5043064

    Windows Installer prompts for credentials; dual-boot Linux may fail

    The update changes Windows Installer repairs to prompt for administrator credentials and addresses security issues. A known dual-boot issue can prevent Linux from starting, and some other issues affect profile pictures and Azure Virtual Desktop.

    As of March 31, 2026, this update is no longer available through Microsoft release channels; Microsoft recommends updating devices to the latest Windows version.
    Known issues: 2 open
    • After installing this update, you might be unable to [change your user account profile picture](https://support.microsoft.com/en-us/windows/change-your-account-picture-3645cdc7-acab-49d2-76a9-4ce7e5e…
    • After installing this security update, you might face issues with booting Linux if you have enabled the dual-boot setup for Windows and Linux in your device.

    Key changes 31 CVEs · 3 changes

    • Improved Windows Installer: When Windows Installer repairs an application, you are now prompted for credentials. Automation scripts may need updating.
    • Improved Dual boot of Windows and Linux: Linux might fail to start on devices set up to dual-boot Windows and Linux. The failure can show a Secure Boot policy violation message...
    • Improved Servicing stack: The component that installs Windows updates receives quality improvements.

    Read update Source: Microsoft

    Builds
    19044.4894 · 19045.4894
    Security
    31 fixed · 1 critical · 3 exploited
  • Windows 10 21H2 / 22H2 Windows 10 21H2 / 22H2 Security update
    Zero-day

    KB5041580

    Exploited Windows flaws and critical TCP/IP risk patched

    Fixes 43 vulnerabilities, including four being exploited and three rated critical. It also adds Secure Boot protections, but can disrupt Linux dual-boot startup and profile-picture changes.

    As of March 31, 2026, this update is no longer available through Microsoft release channels; Microsoft recommends updating devices to the latest Windows version.
    Known issues: 2 open
    • After installing this update, you might be unable to [change your user account profile picture](https://support.microsoft.com/en-us/windows/change-your-account-picture-3645cdc7-acab-49d2-76a9-4ce7e5e…
    • After installing this security update, you might face issues with booting Linux if you have enabled the dual-boot setup for Windows and Linux in your device.

    Key changes 43 CVEs · 6 changes

    • Improved Windows 10, version 22H2: This build includes the improvements from the supported Windows 10, version 21H2 editions.
    • Improved Secure Boot Advanced Targeting (SBAT) and Linux Extensible Firmware Interface (EFI): Windows blocks vulnerable Linux bootloaders from running. The SBAT change is not applied when Windows and Linux dual-booting is detecte...
    • Improved Servicing stack: The component that installs Windows updates receives quality improvements to help devices receive and install Microsoft updates.

    Read update Source: Microsoft

    Builds
    19044.4780 · 19045.4780
    Security
    43 fixed · 3 critical · 4 exploited
  • Windows 10 21H2 / 22H2 Windows 10 21H2 / 22H2 Security update
    Zero-day

    KB5040427

    Exploited MSHTML spoofing flaw patched; RADIUS and BitLocker changes

    The update addresses 75 vulnerabilities, including an exploited MSHTML spoofing flaw and a critical Windows Imaging Component remote code execution flaw. It also changes RADIUS, BitLocker, and shortcut-icon policy behavior.

    As of March 31, 2026, this update is no longer available through Microsoft Update Catalog or other release channels. Microsoft recommends updating devices to the latest Windows version.
    Known issues: 1 open
    • After installing this update, you might be unable to [change your user account profile picture](https://support.microsoft.com/en-us/windows/change-your-account-picture-3645cdc7-acab-49d2-76a9-4ce7e5e…

    Key changes 75 CVEs · 4 changes

    • Improved BitLocker: The default Secure Boot validation profile includes additional PCR measurements.
    • Improved File shortcut icons: IT administrators must configure a policy to allow remote paths in shortcut icons. Without it, icons on Start, the desktop, and the tas...
    • Improved Servicing stack: The component that installs Windows updates receives quality improvements to help devices reliably receive and install Microsoft update...

    Read update Source: Microsoft

    Builds
    19044.4651 · 19045.4651
    Security
    75 fixed · 1 critical · 1 exploited
  • Windows 10 21H2 / 22H2 Windows 10 21H2 / 22H2 Security update
    Zero-day

    KB5039211

    Critical MSMQ flaw and exploited Mark of the Web bypass patched

    Addresses 28 vulnerabilities, including a critical MSMQ remote-code-execution flaw and an exploited Mark of the Web security bypass. It also addresses two LSASS problems and changes how File Explorer tags files from untrusted locations.

    As of March 31, 2026, this update is no longer available from Microsoft release channels. Windows 10, version 21H2 Enterprise, Education, IoT Enterprise, and Enterprise multi-session editions also reached end of service on June 11, 2024.
    Known issues: 3 open
    • After installing this update, you might be unable to [change your user account profile picture](https://support.microsoft.com/en-us/windows/change-your-account-picture-3645cdc7-acab-49d2-76a9-4ce7e5e…
    • Windows devices using more than one (1) monitor might experience issues with desktop icons moving unexpectedly between monitors or other icon alignment issues when attempting to use Copilot in Window…
    • Copilot in Windows (in preview) is not currently supported when your taskbar is located vertically on the right or left of your screen.

    Key changes 28 CVEs · 5 changes

    • Improved Windows 10, version 22H2: This build includes the improvements from the supported Windows 10, version 21H2 editions.
    • Improved File Explorer: File Explorer adds the Mark of the Web tag to files and folders from untrusted locations. This can update the file's LastWriteTime time...
    • Improved Servicing stack: The component that installs Windows updates receives quality improvements to help devices reliably receive and install updates.

    Read update Source: Microsoft

    Builds
    19044.4529 · 19045.4529
    Security
    28 fixed · 1 critical · 1 exploited
  • Windows 10 21H2 / 22H2 Windows 10 21H2 / 22H2 Security update
    Zero-day

    KB5037768

    Exploited MSHTML and DWM flaws patched; VPN failures addressed

    Fixes 47 vulnerabilities, including two exploited flaws in MSHTML and the DWM Core Library, and addresses a VPN connection problem.

    As of March 31, 2026, this update is no longer available through Microsoft Update Catalog or other release channels; Microsoft recommends updating to the latest Windows version.
    Known issues: 3 open
    • After installing this update, you might be unable to [change your user account profile picture](https://support.microsoft.com/en-us/windows/change-your-account-picture-3645cdc7-acab-49d2-76a9-4ce7e5e…
    • Windows devices using more than one (1) monitor might experience issues with desktop icons moving unexpectedly between monitors or other icon alignment issues when attempting to use Copilot in Window…
    • Copilot in Windows (in preview) is not currently supported when your taskbar is located vertically on the right or left of your screen.

    Key changes 47 CVEs · 5 changes

    • Improved Windows 10, version 22H2: This build includes the improvements from supported Windows 10, version 21H2 editions.
    • Improved Servicing stack: Improves the component that installs Windows updates, helping devices receive and install Microsoft updates reliably.
    • Fix VPN: Addresses a known issue that might cause your VPN connection to fail after the April 9, 2024 update or later.

    Read update Source: Microsoft

    Builds
    19044.4412 · 19045.4412
    Security
    47 vulnerabilities fixed · 2 actively exploited
  • Windows 10 21H2 / 22H2 Windows 10 21H2 / 22H2 Security update
    Zero-day

    KB5036892

    Exploited proxy-driver spoofing flaw patched; Copilot limits remain

    Addresses 63 security vulnerabilities, including an actively exploited proxy-driver spoofing flaw. It also lists open Copilot and profile-picture issues.

    As of March 31, 2026, this update is no longer available from Microsoft Update Catalog or other release channels; Microsoft recommends updating to the latest Windows version.
    Known issues: 3 open
    • After installing this update, you might be unable to [change your user account profile picture](https://support.microsoft.com/en-us/windows/change-your-account-picture-3645cdc7-acab-49d2-76a9-4ce7e5e…
    • Windows devices using more than one (1) monitor might experience issues with desktop icons moving unexpectedly between monitors or other icon alignment issues when attempting to use Copilot in Window…
    • Copilot in Windows (in preview) is not currently supported when your taskbar is located vertically on the right or left of your screen.

    Key changes 63 CVEs · 3 changes

    • Improved Windows 10, version 22H2: Version 22H2 includes all improvements from the supported Windows 10 version 21H2 editions.
    • Improved Windows operating system: The update includes miscellaneous security improvements to internal operating system functionality.
    • Improved Servicing stack: The component that installs Windows updates receives quality improvements intended to make it more reliable.

    Read update Source: Microsoft

    Builds
    19044.4291 · 19045.4291
    Security
    63 vulnerabilities fixed · 1 actively exploited
  • Windows 10 21H2 / 22H2 Windows 10 21H2 / 22H2 Security update

    KB5035845

    Hyper-V remote-code flaw addressed; Copilot icon issues remain

    Addresses 35 vulnerabilities, including two critical Hyper-V flaws. Copilot can still disrupt desktop icon placement on multi-monitor devices, and the update is no longer available from Microsoft’s release channels.

    Windows 10 version 21H2 Enterprise, Education, IoT Enterprise, and Enterprise multi-session editions reached end of service on June 11, 2024. Microsoft recommends moving to a newer Windows version to keep receiving security and quality updates.
    Known issues: 2 open
    • Windows devices using more than one (1) monitor might experience issues with desktop icons moving unexpectedly between monitors or other icon alignment issues when attempting to use Copilot in Window…
    • Copilot in Windows (in preview) is not currently supported when your taskbar is located vertically on the right or left of your screen.

    Key changes 35 CVEs · 4 changes

    • Improved Windows 10, version 22H2: Version 22H2 includes the improvements from supported Windows 10 version 21H2 editions.
    • Improved Windows 10, version 21H2: The update includes quality improvements that were part of KB5034843.
    • Improved Windows 10, version 21H2: Internal Windows functionality receives miscellaneous security improvements.

    Read update Source: Microsoft

    Builds
    19044.4170 · 19045.4170
    Security
    35 fixed · 2 critical
  • Windows 10 21H2 / 22H2 Windows 10 21H2 / 22H2 Security update
    Zero-day

    KB5034763

    Closes exploited kernel, SmartScreen and shortcut-file flaws

    Closes three exploited security flaws, including one in the Windows kernel, and addresses several Windows 10 issues. It is no longer available; Microsoft recommends updating to the latest Windows version.

    As of March 31, 2026, this update is no longer available from Microsoft Update Catalog or other release channels. Microsoft recommends updating devices to the latest Windows version.
    Known issues: 2 open
    • Windows devices using more than one (1) monitor might experience issues with desktop icons moving unexpectedly between monitors or other icon alignment issues when attempting to use Copilot in Window…
    • Copilot in Windows (in preview) is not currently supported when your taskbar is located vertically on the right or left of your screen.

    Key changes 38 CVEs · 6 changes

    • Improved Windows 10, version 22H2: Version 22H2 includes the improvements listed for supported Windows 10, version 21H2 editions.
    • Improved Device metadata: Downloads of device metadata from WMIS over HTTPS are more secure.
    • Improved Servicing stack: The component that installs Windows updates receives quality improvements.

    Read update Source: Microsoft

    Builds
    19044.4046 · 19045.4046
    Security
    38 fixed · 1 critical · 3 exploited
  • Windows 10 21H2 / 22H2 Windows 10 21H2 / 22H2 Security update

    KB5034122

    Critical Kerberos and Hyper-V flaws patched; Copilot issues remain

    The update fixes 34 vulnerabilities, including critical flaws in Kerberos and Hyper-V. It is no longer available through Microsoft release channels as of March 31, 2026.

    As of March 31, 2026, this update is no longer available through the Microsoft Update Catalog or other release channels. Microsoft recommends updating devices to the latest version of Windows.
    Known issues: 2 open
    • Windows devices using more than one (1) monitor might experience issues with desktop icons moving unexpectedly between monitors or other icon alignment issues when attempting to use Copilot in Window…
    • Copilot in Windows (in preview) is not currently supported when your taskbar is located vertically on the right or left of your screen.

    Key changes 34 CVEs · 5 changes

    • Improved Windows 10, version 22H2: This build includes all the improvements from supported Windows 10 version 21H2 editions.
    • Improved Servicing stack: The component that installs Windows updates receives quality improvements to help devices receive and install Microsoft updates reliabl...
    • Fix ActiveX scroll bar: The ActiveX scroll bar works in IE mode again.

    Read update Source: Microsoft

    Builds
    19044.3930 · 19045.3930
    Security
    34 fixed · 2 critical