Windows 10: April 2026 Windows Update Breaks Third-Party Backup Software by Blocking Vulnerable Driver

Microsoft has confirmed that the security update scheduled for April 2026 will include the psmounterex.sys driver in its Vulnerable Driver Blocklist. This change causes some third-party backup programs that depend on the driver for mounting images and creating VSS snapshots to fail. The block was introduced to fix CVE-2023-43896, a high-severity buffer overflow vulnerability that could allow privilege escalation or arbitrary code execution.

Affected software includes Macrium Reflect, Acronis Cyber Protect Cloud, UrBackup Server, and NinjaOne Backup, all running on Windows 11, Windows 10, and Windows Server.

What Fails and What Does Not


Full image backup creation may still succeed on affected systems. The failures happen specifically during image-mount operations, which means browsing backups or restoring from them will not work. Users might see the error message "The backup has failed because Microsoft VSS has timed out during the snapshot creation" or the error code VSS_E_BAD_STATE.

Event Viewer will display Code Integrity errors indicating that psmounterex.sys was blocked from loading. The relevant event to look for is Event ID 3077 with Policy ID {D2BDA982-CCF6-4344-AC5B-0B44427B6816} in the Code Integrity Operational log.

How to Check If Your System Is Affected

1. Right-click the Start button and choose Event Viewer.
2. Navigate to Applications and Services Logs> Microsoft > Windows > CodeIntegrity > Operational.
3. Look for Event ID 3077 in the center pane.

If the event appears and mentions the psmounterex.sys driver in enforcement mode, your system is affected.

Microsoft’s Recommended Fix for Backup Failures Caused by the April 2026 Update


Microsoft recommends updating to a newer version of the affected backup application that utilizes drivers not listed on the blocklist. Uninstalling or pausing the April update is not advised, as the block addresses an actively exploitable vulnerability. Backup software vendors are expected to release updated versions with compliant drivers.

The April 2026 update has led to several issues, including problems beyond the backup driver block. Microsoft has confirmed that some Windows Server 2025 devices may boot into BitLocker recovery mode after installing KB5082063.

In addition, out-of-band updates were released to fix Windows Server update failures and restart loops on domain controllers caused by the April security updates.

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How to enable Microsoft Vulnerable Driver Blocklist

Hello,

I have a new PC with windows 11 pro installed. Vulnerable Driver Block list is greyed out. If I turn off Memory integrity then I can enable Driver block list. However when my PC restarts it is still greyed out when MI is on?

Any suggestions please?

Thank you

Chris

 

WPA2 Vulnerability Found

A small update with regards to the Microsoft fix. The fix itself is sufficient to solve the issue on Windows, even if your WiFi device has no driver update, with one caveat:

Does this security update fully address these vulnerabilities on Microsoft Platforms, or do I need to perform any additional steps to be fully protected?
The provided security updates address the reported vulnerabilities; however, when affected Windows based systems enter a connected standby mode in low power situations, the vulnerable functionality may be offloaded to installed Wi-Fi hardware. To fully address potential vulnerabilities, you are also encouraged to contact your Wi-Fi hardware vendor to obtain updated device drivers. For a listing of affected vendors with links to their documentation, review the ICASI Multi-Vendor Vulnerability Disclosure statement here: http://www.icasi.org/wi-fi-protected-access-wpa-vulnerabilities

Source: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2017-13080

 

Microsoft blocks Windows 10 April Update for Intel SSD 600p Series

Microsoft is blocking some Intel SSDs from installing the April 2018 Update after discovering an incompatibility issue that causes performance and stability issues. In short, the problem was explained by Microsoft as: “When attempting to upgrade to Window 10 April 2018 Update select devices with certain Intel SSDs may enter a UEFI screen reboot or crash repeatedly.” Microsoft says that this issue has no workaround and that those that have attempted to update Windows 10 to the Windows 10 April 2018 Update should revert back to Windows 10 Fall Creators Update version 1709.

Unfortunately, the announcement by Microsoft fails to list what specific Intel SSD models are having issues with the OS update. We contacted Intel and discovered that the Intel SSD 600p Series of client drives that was first introduced to the market in 2016 is the most popular drive that is having issues.

Source: Legit Reviews