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Microsoft Releases November and December 2025 Patch Tuesday Updates for Windows 11

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1 unique sources, 11 articles

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Microsoft has fully resolved the Windows 11 'UNMOUNTABLE_BOOT_VOLUME' boot failure issue in the February 2026 Patch Tuesday security update (KB5077181), addressing a problem that left commercial systems unbootable after failed December 2025 updates. The issue, which affected Windows 11 versions 25H2 and 24H2, was initially mitigated by the optional KB5074105 preview update but is now considered fully resolved. Devices that became unbootable before the fix may still require manual recovery or enterprise support. Earlier, Microsoft linked the January 2026 boot failures to failed attempts to install the December 2025 security update, which left systems in an unstable state. The company had also released emergency out-of-band updates to fix an unrelated issue causing Microsoft Outlook to freeze when PST files were stored in cloud services. Prior updates included fixes for gaming performance issues, broken localhost HTTP connections, and Windows Recovery Environment (WinRE) problems, alongside cumulative updates for November and December 2025 introducing new features and addressing security vulnerabilities across Windows 11 versions 25H2/24H2 and 23H2.

Timeline

  1. 16.02.2026 00:08 1 articles · 23h ago

    Microsoft Fully Resolves Windows 11 Boot Failures in February 2026 Patch Tuesday

    Microsoft has fully resolved the 'UNMOUNTABLE_BOOT_VOLUME' boot failure issue in the February 2026 Patch Tuesday security update (KB5077181). The issue, which affected Windows 11 versions 25H2 and 24H2, was caused by failed December 2025 updates that left systems in an 'improper state.' Installing the January 2026 security updates on these devices triggered the boot failures, rendering them unbootable and requiring manual recovery. The February 2026 update follows an initial mitigation released in the optional KB5074105 preview update on January 29, 2026, which helped prevent additional systems from encountering the issue. However, devices that became unbootable before the February update may still require manual recovery or assistance from Microsoft Support for Business. Microsoft confirmed the resolution in a private enterprise advisory, noting that the issue was limited to commercial physical devices, with no reports of home users or virtual machines being affected. The advisory was not publicly disclosed, and the reason for this limited communication remains unclear.

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  2. 30.01.2026 14:02 2 articles · 17d ago

    Microsoft Releases KB5074105 Preview Update Fixing Boot and Sign-in Issues

    Microsoft released the optional KB5074105 preview cumulative update for Windows 11, addressing critical issues such as boot failures, sign-in problems, and activation errors. This non-security update included 32 changes, focusing on quality improvements and bug fixes for testing before the next Patch Tuesday release. Key fixes included resolving an issue where Explorer.exe hangs during the first login when certain apps are configured as startup apps, a bug causing system unresponsiveness during startup with Windows Boot Manager debugging enabled, and iSCSI boot failures triggering an 'Inaccessible Boot Device' error. The update also addressed a Windows license migration issue that prevented PCs from registering with the Windows Activation server during upgrades. New features and improvements included expanded Cross-Device Resume functionality, allowing users to continue activities from Android phones on their PCs, and extended Windows Hello Enhanced Sign-in Security (ESS) support for peripheral fingerprint sensors. Additional fixes included resolving a User Account Control (UAC) issue causing PCs to freeze when running Windows Terminal elevated from a non-admin account, a graphics error related to dxgmms2.sys causing KERNEL_SECURITY_CHECK_FAILURE, and a Windows Sandbox startup failure displaying error 0x800705b4. The update was optional and could be installed via Windows Update or manually from the Microsoft Update Catalog. It updated Windows 11 25H2 and 24H2 devices to builds 26200.7705 and 26100.7705, respectively. This update also served as an initial mitigation for the 'UNMOUNTABLE_BOOT_VOLUME' boot failures, preventing additional systems from being affected, though it did not resolve the issue for already impacted devices.

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  3. 25.01.2026 15:20 1 articles · 22d ago

    Microsoft Releases Emergency Out-of-Band Updates for Outlook Freezing Issue

    Microsoft released emergency out-of-band (OOB) updates on Saturday to fix an issue that caused Microsoft Outlook to freeze when PST files are stored in cloud services such as OneDrive or Dropbox. The issue primarily affects the Outlook class, which is typically used in enterprise environments.

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  4. 13.01.2026 20:53 4 articles · 1mo ago

    Microsoft Releases January 2026 Patch Tuesday Updates for Windows 11

    Microsoft has resolved a known issue causing security applications to incorrectly flag WinSqlite3.dll as vulnerable to CVE-2025-6965. The issue affected various Windows platforms, including Windows 10, Windows 11, and Windows Server 2012 through Windows Server 2025. Microsoft updated WinSqlite3.dll in the January 13, 2026 updates to address false positive detections. Microsoft is investigating reports that some Windows 11 devices are failing to boot with 'UNMOUNTABLE_BOOT_VOLUME' errors after installing the January 2026 Patch Tuesday security updates. The issue affects Windows 11 version 25H2 and all editions of Windows 11 version 24H2 after installing the KB5074109 cumulative update. Affected devices display a black Windows crash screen stating, 'Your device ran into a problem and needs a restart. You can restart.' Only physical devices are reported as impacted by the bug, with no virtual machines affected. Microsoft has now linked these boot failures to failed attempts to install the December 2025 security update, which left systems in an 'improper state' after rollback. The company is working on a partial resolution to prevent additional devices from encountering the no-boot scenario but notes that this will not repair already affected systems or prevent devices from entering the improper state initially. The investigation into the root cause of the update failures and improper state is ongoing.

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  5. 09.12.2025 20:31 1 articles · 2mo ago

    Microsoft Releases December 2025 Patch Tuesday Updates for Windows 11

    Microsoft has released Windows 11 KB5072033 and KB5071417 cumulative updates for versions 25H2/24H2 and 23H2. These updates address security vulnerabilities, bugs, and introduce new features. New features include dark mode support for dialogs in File Explorer, new Virtual Workspaces settings, desktop spotlight options, simplified File Explorer context menu, full-screen experience for gaming, haptic feedback for pens, improved keyboard backlight performance, mobile device settings, OneDrive icon in settings, Quick Machine Recovery, updated keyboard settings, updated taskbar animations, sharing apps with Copilot, updated widgets, improved Windows Share, display and graphics performance improvements, Game Pass branding updates, and improved Start menu search panel. Microsoft will not release optional updates in December, but Patch Tuesday updates will continue as scheduled.

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  6. 21.11.2025 20:02 1 articles · 2mo ago

    Microsoft Releases KB5072753 Out-of-Band Update for Windows 11

    Microsoft has released the KB5072753 out-of-band cumulative update to fix a known issue causing the November 2025 KB5068966 hotpatch update to reinstall on Windows 11 systems repeatedly. This update is a cumulative update that includes improvements and security fixes from the KB5068966 security update. Microsoft recommends applying the KB5072753 update instead of the November 2025 hotpatch update (KB5068966) for Windows 11, version 25H2 devices.

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  7. 11.11.2025 20:32 3 articles · 3mo ago

    Microsoft Releases November 2025 Patch Tuesday Updates for Windows 11

    Microsoft has released Windows 11 KB5068861 and KB5068865 cumulative updates for versions 25H2/24H2 and 23H2. These updates address security vulnerabilities, bugs, and add new features. New features include a new Start menu UI, battery icons on the lock screen, Microsoft 365 Copilot page, and updated battery icons in the taskbar. The updates also fix issues in various components, including Taskbar, File Explorer, Input, Narrator, Open and Save Dialog, Remote Credential Guard, Sign-in, and Task Manager. This is the last update for Windows 11 23H2 as its support ends in November 2025. Microsoft will not release optional updates in December, but Patch Tuesday updates will continue as scheduled. Additionally, Microsoft has released the KB5072753 out-of-band cumulative update to fix a known issue causing the November 2025 KB5068966 hotpatch update to reinstall on Windows 11 systems repeatedly. This update is recommended for Windows 11, version 25H2 devices instead of the November 2025 hotpatch update (KB5068966).

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  8. 14.10.2025 20:46 3 articles · 4mo ago

    Microsoft Releases October 2025 Patch Tuesday Updates for Windows 11

    Microsoft has released cumulative updates KB5066835 and KB5066793 for Windows 11 versions 25H2/24H2 and 23H2. These updates address security vulnerabilities and various issues, including fixes for browsers, gaming, PowerShell, and Windows Hello. New features introduced include AI actions in File Explorer, improved Narrator accessibility, and enhanced passkey management. The updates also mark the second-to-last update for Windows 11 23H2, with support ending in November 2025. Nvidia has confirmed that the October 2025 Windows 11 updates (KB5066835) cause gaming performance issues on Windows 11 24H2 and 25H2 systems. Nvidia released the GeForce Hotfix Display Driver version 581.94 to address these issues. The October updates also caused other issues such as broken localhost HTTP connections, smart card authentication problems, and broken Windows Recovery Environment (WinRE) on systems with USB mice and keyboards.

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Information Snippets

Similar Happenings

Microsoft February 2026 Patch Tuesday Addresses 6 Zero-Days and 59 Flaws

Microsoft's February 2026 Patch Tuesday addresses 59 vulnerabilities, including 6 actively exploited zero-days and 3 publicly disclosed flaws. The updates include fixes for 5 critical vulnerabilities, with three being security feature bypass flaws in various Microsoft products. The zero-days span components such as Windows Shell, MSHTML Framework, Microsoft Word, Desktop Window Manager, Windows Remote Access Connection Manager, and Windows Remote Desktop Services. Microsoft issued an out-of-band patch for one of the zero-days, CVE-2026-21514, highlighting its urgency. The updates also cover a range of other vulnerabilities, including elevation of privilege, security feature bypass, remote code execution, information disclosure, denial of service, and spoofing flaws. Additionally, Microsoft has begun rolling out updated Secure Boot certificates to replace expiring 2011 certificates. Other vendors, including Adobe, BeyondTrust, CISA, Cisco, Fortinet, Google, n8n, and SAP, have also released security updates or advisories.

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Windows 11 Update KB5074109 Causes Outlook Freezes for POP Users

Microsoft has released emergency out-of-band updates on January 25, 2026, to address an issue causing Microsoft Outlook to freeze for users with POP email accounts. The problem, which affects users of Windows 11 25H2 and 24H2, Windows 10, and multiple Windows Server platforms, occurs when PST files are stored in cloud storage like OneDrive or Dropbox. The issue prevents Outlook from exiting properly and restarting after being closed. Users can temporarily resolve the issue by uninstalling the KB5074109 update or accessing their email accounts via webmail or moving their Outlook PST files out of OneDrive. The out-of-band updates include fixes for other issues, such as access to Microsoft 365 Cloud PC sessions and Secure Launch bugs.

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Windows 11 23H2 Shutdown Issue with System Guard Secure Launch

Windows 11 23H2 devices with System Guard Secure Launch enabled fail to shut down properly after installing the January 13, 2026, cumulative update (KB5073455). Affected systems restart instead of shutting down or entering hibernation. This issue impacts Enterprise and IoT editions of Windows 11, version 23H2, as well as Windows 10 22H2, Windows 10 Enterprise LTSC 2021, and Windows 10 Enterprise LTSC 2019 with Virtual Secure Mode (VSM) enabled. Microsoft has provided a temporary workaround for shutdown but no solution for hibernation. The company is also addressing a separate bug in the January 2026 KB5074109 update causing Remote Desktop connection failures. Microsoft has released an out-of-band update (KB5077797) to fix the shutdown issue in Windows 11 23H2.

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Microsoft January 2026 Patch Tuesday Addresses 3 Zero-Days, 114 Flaws

Microsoft's January 2026 Patch Tuesday addressed 114 vulnerabilities, including three zero-days: one actively exploited (CVE-2026-20805) and two publicly disclosed (CVE-2026-21265 and CVE-2023-31096). The updates covered a range of flaw types, with eight classified as 'Critical,' including remote code execution and elevation-of-privilege vulnerabilities. Additionally, Microsoft released emergency out-of-band security updates to patch a high-severity Microsoft Office zero-day vulnerability (CVE-2026-21509) exploited in attacks, affecting multiple Office versions. The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has added CVE-2026-20805 and CVE-2026-21509 to its Known Exploited Vulnerabilities (KEV) catalog, mandating Federal Civilian Executive Branch (FCEB) agencies to apply the latest fixes by February 3, 2026, and February 16, 2026, respectively. The flaw was discovered by the Microsoft Threat Intelligence Center (MSTIC), the Microsoft Security Response Center (MSRC), and the Office Product Group Security Team, and affects several versions of Microsoft Office 2016, 2019, LTSC 2021, LTSC 2024, and Microsoft 365 Apps for Enterprise.

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Windows Updates Cause RemoteApp Connection Failures in Azure Virtual Desktop

Recent Windows updates, including the November 2025 KB5070311 non-security update and a recent Windows 365 update, are causing RemoteApp connection failures in Azure Virtual Desktop environments on Windows 11 24H2/25H2 and Windows Server 2025 devices. This issue primarily affects enterprise users, leaving full desktop sessions unaffected. The incident began on Tuesday at 19:00 UTC, with users experiencing sign-in failures and intermittent access issues to their Cloud PCs. Microsoft has provided temporary mitigations, including a registry key modification, a Known Issue Rollback (KIR) for Windows Pro and Enterprise devices, and workarounds such as accessing Cloud PCs through the Windows App Web Client or using the Remote Desktop client for Windows. Microsoft is working on a permanent fix but has not provided a timeline.

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