Event Viewer

Winsage
June 29, 2026
Major PC manufacturers, including HP, Dell, ASUS, Lenovo, MSI, Acer, Samsung, LG, and Microsoft’s Surface division, have provided guidance on transitioning to new Secure Boot certificates as the expiration of Microsoft’s 2011 certificates approaches. The expiration will occur in three phases: Microsoft Corporation KEK CA 2011 expired on June 24, 2026; Microsoft UEFI CA 2011 expired on June 27, 2026; and Microsoft Windows Production PCA 2011 is set to expire on October 19, 2026. Microsoft has begun rolling out replacement certificates through Windows Update, contingent on OEMs providing compatible BIOS updates. ASUS offers detailed documentation for both consumer and commercial devices, confirming that most users will receive updates automatically. Lenovo provides direct download links for BIOS updates organized by product family and specifies which products will not receive updates. Dell's support article covers its entire product lineup, noting that devices with an End of Service Life before January 1, 2026, will not receive updates. HP outlines a dual-track approach for updates, with specific timelines for commercial PCs. Microsoft's Surface devices receive updates directly from Microsoft, while MSI categorizes guidance based on processor generation for its laptops. Acer emphasizes backing up the BitLocker recovery key and provides a model table for confirmed BIOS release dates. Samsung confirms that all PCs running Windows 10 or 11 will function normally post-expiration, but security updates will cease. LG has released a guide for checking BIOS updates for its PCs. To verify if a PC has the 2023 certificates, users can check the Secure Boot section in Windows Security. A green checkmark indicates successful application, while yellow or red icons indicate pending updates or incompatibility. Microsoft has pushed the certificates to all eligible devices as of June 2026.
Winsage
June 15, 2026
Microsoft has expanded the rollout of the Secure Boot 2023 certificate update to more Windows 11 and Windows 10 devices with the June 2026 Patch Tuesday update (KB5094126). This update aims to ensure that most supported consumer PCs are classified as high confidence, meaning necessary certificates are either installed or will be applied automatically. Secure Boot is a firmware security feature that verifies the software attempting to load during the startup process, blocking unauthorized software. The certificates supporting Secure Boot, issued in 2011, are expiring in stages starting June 24, 2026, prompting Microsoft to deploy replacement certificates. Most home users do not need to take manual action as the updates will occur automatically via Windows Update. Users can check their Secure Boot certificate status in the Windows Security app. A yellow warning indicates pending compatibility data, while a red alert suggests a firmware incompatibility requiring a BIOS update. Multiple reboots during the update process are normal, and a new SecureBoot folder in Windows is for staging cryptographic files. Older PCs may experience longer update times, and some may not receive updates due to firmware issues. HP users should check for BIOS updates if encountering BitLocker recovery loops. IT administrators should monitor device classifications and manually initiate updates for devices not in the high confidence category. Devices with Secure Boot disabled cannot receive updates, leaving them vulnerable. The expiration of the Microsoft Corporation KEK CA 2011 certificate on June 24 does not immediately affect device functionality, but it limits Microsoft's ability to sign new bootkit blacklist updates.
Winsage
June 8, 2026
Microsoft has integrated Sysmon into Windows 11 through a system update, allowing it to operate in the background and log activities in the Windows Event Log. Indicators of suspicious processes include the absence of icons or descriptions, incorrect parent processes, spelling errors in names, unsigned executable files, packed executables, suspicious DLLs or services, open TCP/IP endpoints, and unusual URLs or character strings. To install Sysmon, users must access the Control Panel, enable Sysmon, and restart their PC. Activation requires running a command in the Command Prompt. Sysmon logs can be viewed in the Event Viewer under Microsoft > Windows > Sysmon > Operational. Users can filter events using an XML configuration file. After analysis, suspicious processes should be scanned with antivirus software, and files can be uploaded to VirusTotal for further examination. Sysmon continuously logs events, while Process Monitor captures snapshots of running processes, and both tools are available for free from Microsoft.
Winsage
June 1, 2026
Microsoft has identified the root cause of installation issues related to the May 2026 update for Windows operating system and is rolling out a solution through an optional update, KB5089573. The May 12, 2026, Patch Tuesday update (KB5089549) introduced enhancements but many users faced installation failures due to error code “0x800f0922,” indicating insufficient space on the EFI System Partition (ESP). The ESP is critical for boot files and typically occupies around 256MB. Users can check ESP storage using a specific command. Low ESP space can lead to update failures, particularly when it drops below 10MB. Microsoft has rolled back problematic code and provided a fix in the optional update KB5089573, which resolves ESP space issues and ensures future updates will proceed smoothly. Users are encouraged to install this update or wait for the next scheduled Patch Tuesday update on June 9, 2026.
Winsage
May 7, 2026
The Windows 11 security update KB5083769, released on April 14, 2026, introduces changes to the psmounterex.sys driver, causing compatibility issues with third-party backup solutions such as Macrium Reflect, Acronis Cyber Protect Cloud, UrBackup Server, and NinjaOne Backup. Microsoft states this is a necessary security adjustment, not a bug. The update also adds known vulnerable kernel drivers to a blocklist to enhance system security. Users can check if a driver is blocked by using the Event Viewer and looking for Event ID 3077 associated with a specific Policy ID.
Winsage
May 5, 2026
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 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
April 28, 2026
Windows 11 updates have significantly increased in size, with monthly cumulative updates often exceeding 4GB and some approaching 5GB. One update can expand to nearly 9GB when extracted. Microsoft has shifted to delivering Latest Cumulative Updates (LCUs), which include all previous fixes, leading to larger update sizes over time. The introduction of Checkpoint Cumulative Updates aims to reduce this growth by establishing periodic baselines, but the effectiveness has been mixed. The May 2025 cumulative update saw a size increase from approximately 6.5GB to nearly 9GB, with new MSIX files related to semantic search and on-device AI contributing to this growth. Windows Update uses applicability logic to minimize download sizes for users, but enterprises must download full packages, resulting in increased storage costs. The average yearly storage cost for enterprises rose from about 11 GB in 2024 to 52 GB by 2026. Users can check their actual download sizes through the Windows Update settings and Event Viewer logs.
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