On Windows 11, the security update KB5083769 introduces a new behavior using the psmounterex.sys driver that causes third-party backup solutions to fail, and Microsoft recommends updating your backup software since this isn't a bug with the operating system.
On April 14, 2026, the software giant made available the "2026-04 Security Update (KB5083769) (Build 26200.8246)" for Windows 11 with new features, improvements, and security fixes. However, Microsoft also introduced a change that adds known "vulnerable kernel drivers" to the driver blocklist to improve system security.
