Windows 10 Gets New Security Update KB5099539 with Bug Fixes and Secure Boot Improvements

Microsoft has released KB5099539, a new security update for Windows 10 version 22H2, Windows 10 Enterprise LTSC 2021, and Windows 10 IoT Enterprise LTSC 2021. The update delivers the latest security patches, resolves several bugs, and continues Microsoft’s rollout of updated Secure Boot certificates.

Eligible systems enrolled in the Extended Security Updates (ESU) program will receive the update automatically.

Security Update for Windows 10 ESU Devices

KB5099539 focuses on addressing recently discovered security vulnerabilities in Windows 10.

After installation, supported systems are updated to Windows 10 Build 19045.7548, ensuring they remain protected against the latest threats.

Unlike recent Windows 11 releases, this update does not introduce new features, instead concentrating on security and stability improvements.

Several Windows 10 Bugs Fixed

Microsoft has also resolved a number of issues affecting everyday use, including:

• A File Explorer bug that prevented OneDrive shortcuts from working when File Explorer was launched with administrator privileges.
• An issue that displayed an incorrect error message when deleting files.
• Problems affecting certain keyboard shortcuts.

These fixes improve the overall reliability of Windows 10 without changing its user interface or functionality.

Secure Boot Certificate Rollout Continues

The update also continues Microsoft’s deployment of new Secure Boot certificates.

The existing certificates used by many Windows devices began expiring in June 2026, prompting Microsoft to gradually distribute replacements through Windows Update.

According to Microsoft, devices that have not yet received the updated certificates will continue to boot normally and receive regular Windows updates. The new certificates will continue rolling out over the coming months.

Available Only Through the ESU Program

KB5099539 is available only for Windows 10 devices enrolled in Microsoft’s Extended Security Updates (ESU) program.

The ESU program allows eligible systems to continue receiving critical security updates after Windows 10’s end of support, with coverage extending until October 12, 2027.

For users participating in the program, the update installs automatically through Windows Update, meaning no manual action is required beyond allowing the installation to complete.