Server 2025 Archives

Winsage

May 23, 2026

CVE-2026-45585: YellowKey BitLocker Bypass

BitLocker, a security feature for data protection, has a vulnerability identified as CVE-2026-45585, also known as YellowKey, which allows unauthorized access to encrypted data on Windows 11 versions 24H2, 25H2, 26H1, and Windows Server 2025. This flaw does not compromise BitLocker’s encryption but affects the recovery environment supporting it. The vulnerability can be exploited locally through the Windows Recovery Environment (WinRE) by an attacker with physical access, who can trigger an unrestricted shell and access the BitLocker-protected volume. Microsoft has provided two mitigation strategies: modifying the WinRE image to remove the autofstx.exe entry and transitioning from TPM-only protection to a TPM+PIN requirement at startup. The exploit poses challenges for detection, as it occurs pre-boot and currently lacks vendor-published indicators of compromise. Organizations using BitLocker for unattended devices are particularly at risk, as the vulnerability can lead to loss of confidentiality if an attacker gains access before the legitimate user.

Winsage

May 21, 2026

A Windows 11 bug blocks all updates since February. Here’s what to do

A segment of Windows 11 users has been unable to receive updates since February due to issues stemming from the January Preview Update, which caused download timeouts. This has resulted in missed security patches and critical updates related to Secure Boot certificates. Users may experience crashes during the update process, indicated by the error code 0x80010002. To check if affected, users can view their update history in Settings; if no updates have been installed since January and updates have not been paused, they are likely impacted. Microsoft is working on a fix linked to download timeout changes and firewall settings. A Known-Issue Rollback (KIR) can be executed to revert to a previous state before the problematic update, restoring normal functionality. This rollback is available for specific Windows 11 versions and Windows Server 2025.

Winsage

May 5, 2026

April 2026 Windows Update Breaks Third-Party Backup Software by Blocking Vulnerable Driver

Microsoft will include the psmounterex.sys driver in its Vulnerable Driver Blocklist in the April 2026 security update, affecting third-party backup applications that use this driver for image mounting and Volume Shadow Copy Service (VSS) snapshots. This decision addresses CVE-2023-43896, a critical buffer overflow vulnerability. Affected software includes Macrium Reflect, Acronis Cyber Protect Cloud, UrBackup Server, and NinjaOne Backup on Windows 11, Windows 10, and Windows Server platforms. Users may face issues during image-mount operations, receiving error messages related to VSS timeouts and Code Integrity errors in the Event Viewer. To check if a system is affected, users can look for Event ID 3077 in the Code Integrity Operational log. Microsoft recommends upgrading to newer versions of backup applications that do not use blocked drivers and advises against uninstalling or delaying the April update. Additionally, the update may cause certain Windows Server 2025 devices to boot into BitLocker recovery mode and has led to out-of-band updates for Windows Server update failures and restart loops on domain controllers.

Winsage

May 4, 2026

Microsoft confirms April Windows updates cause backup failures

Microsoft has acknowledged that the April 2026 security updates have disrupted the functionality of various third-party backup applications using the psmounterex.sys driver, raising concerns among users. The issue primarily affects software leveraging the Volume Shadow Copy Service (VSS) snapshots, leading to failures due to VSS service timeouts. Notable impacted products include Macrium Reflect, Acronis Cyber Protect Cloud, UrBackup Server, and NinjaOne Backup, used on Windows 11, Windows Server, and Windows 10 devices. Disruptions can manifest as failures to mount backup image files, errors or timeouts when browsing or restoring from backup images, and error messages related to VSS timeouts. Microsoft updated its support documentation to clarify that the April updates included a security hardening change that added psmounterex.sys to the vulnerable driver blocklist to protect against a high-severity buffer overflow vulnerability (CVE-2023-43896). Affected users are advised to upgrade to newer application versions with updated drivers and not to uninstall or pause the security update. Users can check if the Microsoft Vulnerable Driver Blocklist is blocking a driver by looking for Event ID 3077 in the Code Integrity Operational log. Additionally, Microsoft has alerted users that some Windows Server 2025 devices may boot into BitLocker recovery mode after installing the KB5082063 update and has issued out-of-band updates to address installation failures and restart loops affecting Windows Server systems after the April 2026 updates.

Winsage

May 1, 2026

Windows 11 KB5083631 update released with 34 changes and fixes

Microsoft has released the KB5083631 optional cumulative update for Windows 11, featuring 34 enhancements aimed at improving user experience and system performance. Key features include a new Xbox mode for immersive gaming, improved performance for startup applications, enhanced security for batch files and CMD scripts, haptic feedback on supported devices, improvements to Secure Boot, and updates to Kerberos authentication. The update also addresses issues with Windows Security event logging, eliminates a white flash in dark mode, and increases the reliability of explorer.exe processes. Users can install the update via Windows Settings under Windows Update. After installation, Windows 11 devices will be updated to builds 26100.8328 and 26200.8328. Additionally, updated Secure Boot certificates are being rolled out, and some Windows Server 2025 devices may require a BitLocker recovery key after the update.

Winsage

May 1, 2026

April KB5083769 Windows 11 update causes backup software failures

The KB5083769 security update released in April 2026 has disrupted the functionality of various third-party backup applications on Windows 11 versions 24H2 and 25H2, primarily due to issues with the Volume Shadow Copy Service (VSS). Affected applications include Acronis Cyber Protect Cloud, Macrium Reflect, NinjaOne Backup, and UrBackup Server. Users have reported receiving an error message indicating that backups have failed due to VSS timeouts. Acronis has acknowledged the issue, stating it affects both Windows 11 Pro and Home editions, and warns of potential broader system issues. A temporary solution involves uninstalling the KB5083769 update or pausing Windows updates. Additionally, Microsoft has issued out-of-band updates for critical issues affecting Windows Server systems and warned that some Windows Server 2025 devices may encounter BitLocker recovery prompts after installing the KB5082063 update.

Winsage

April 21, 2026

Planning your path to Windows Server 2025: What organizations are prioritizing in 2026 | Microsoft Windows Server Blog

Windows Server remains essential for critical workloads globally, with organizations needing to improve security, streamline patching, and maintain resilience in complex hybrid environments. The Windows Server Summit 2026 will take place from May 11–13, focusing on actionable guidance in security, patching, resiliency, and hybrid operations. Key areas of investment for 2026 include upgrade planning for Windows Server 2025, hybrid governance and management through Azure Arc, and operational consistency at scale with monitoring and patch automation. The Summit will provide insights into future Windows Server developments and facilitate direct interaction with Microsoft's product team. Attendees will receive practical guidance on upgrade strategies, operational patterns, security considerations, and hybrid management scenarios. Common triggers for evaluating changes include planning transitions to Windows Server 2025, reassessing patch cadence, standardizing hybrid operations, and addressing operational fragmentation. The event is aimed at enterprise IT professionals seeking to secure and modernize their Windows Server environments.

Winsage

April 20, 2026

Planning your path to Windows Server 2025: What organizations are prioritizing in 2026 | Microsoft Windows Server Blog

Windows Server is facing increasing operational demands due to the need for quicker patch cycles, enhanced system resilience, and complexities from hybrid environments. The Windows Server Summit 2026, scheduled for May 11–13, will address these challenges by providing actionable insights on security, patching, resiliency, and hybrid operations. Key areas of focus for organizations include upgrade planning for Windows Server 2025, hybrid governance and management through Azure Arc, and maintaining operational consistency at scale with monitoring and patch automation. The Summit will feature scenario-based technical sessions and live Q&A opportunities with Microsoft’s engineering and product teams. Common triggers for reevaluation of Windows Server operations include plans to transition to Windows Server 2025, reassessment of patch cadence, efforts to standardize operations across hybrid deployments, and recognition of operational fragmentation. The event aims to provide practical guidance for enterprise IT professionals to secure and modernize their Windows Server environments.

Winsage

April 20, 2026

Emergency Update for Windows Server Following Reboot Issues

Microsoft has released emergency updates for various versions of Windows Server due to issues arising from the April 2026 Patch Tuesday security updates. A significant problem was a reboot loop affecting domain controllers caused by crashes of the Local Security Authority Subsystem Service (LSASS), which disrupted authentication services. This issue was especially problematic during the setup of new domain controllers. Additionally, some Windows Server 2025 systems encountered difficulties in installing the security update KB5082063. The out-of-band update (KB5091157) for Windows Server 2025 addresses both the installation failure and the domain controller restart issue. Other updates targeting the domain controller restart problem were released for additional supported Windows Server versions. Microsoft has introduced an out-of-band update for seven versions, including KB5091157 for Windows Server 2025 and KB5091571 for Windows Server, version 23H2. Furthermore, some Windows Server 2025 devices may boot into BitLocker recovery mode after the update, requiring users to enter a BitLocker recovery key.

Winsage

April 20, 2026

Microsoft releases emergency updates to fix Windows Server issues

Microsoft has confirmed that some administrators are experiencing difficulties installing the KB5082063 security update on Windows Server 2025. This month's Patch Tuesday updates have caused certain Windows servers, especially those with domain controller roles, to enter a restart loop due to failures in the Local Security Authority Subsystem Service (LSASS). Microsoft has released emergency out-of-band updates, including KB5091157 for Windows Server 2025, to address both the installation failure and the restart issues. Additionally, some Windows Server 2025 devices may boot into BitLocker recovery mode after installing the KB5082063 update. A bug affecting Windows Server 2019 and Windows Server 2022 that caused unexpected upgrades to Windows Server 2025 has also been resolved. Microsoft has issued various emergency updates throughout the year to address other issues, including a Bluetooth device visibility bug and vulnerabilities in the Routing and Remote Access Service (RRAS).