Summary

Microsoft has acknowledged that the April 2026 security updates are causing failures in third-party backup applications. The issue is linked to the psmounterex.sys driver, which is part of these applications.

Key Points

• Microsoft confirmed the issue with the April 2026 security updates.
• The problem affects third-party backup applications using the psmounterex.sys driver.
• The issue has been identified as a result of the latest security updates.
• No specific CVE numbers were mentioned in relation to this issue.

Analysis

The confirmation from Microsoft highlights the unintended consequences that can arise from security updates, especially when they interact with third-party software. This issue underscores the importance of thorough testing and compatibility checks before deploying updates in production environments. The disruption to backup applications could pose significant risks to data integrity and availability for affected organizations.

Conclusion

IT professionals should carefully evaluate the impact of the April 2026 updates on their systems, particularly if using third-party backup solutions. It is recommended to monitor Microsoft's communications for any patches or workarounds and consider delaying the update deployment until a resolution is provided.