KB5065425: [File sharing] Fixed

September 9, 2025—KB5065425 (OS Build 25398.1849)

Improvements
This security update contains fixes and quality improvements from KB5063899 (released August 12, 2025). The following summary outlines key issues addressed by this update. Also, included are available new features. The bold text within the brackets indicates the item or area of the change.

• [App compatibility (known issue)] Fixed: Addresses an issue that caused non-admin users to receive unexpected User Account Control (UAC) prompts when MSI installers perform certain custom actions. These actions might include configuration or repair operations in the foreground or background, during the initial installation of an application.

This issue could prevent non-admin users from running apps that perform MSI repairs, including Office Professional Plus 2010 and multiple applications from Autodesk (including AutoCAD). This fix reduces the scope for requiring UAC prompts for MSI repairs and enables IT admins to disable UAC prompts for specific apps by adding them to an allowlist.

For more information, see Unexpected UAC prompts when running MSI repair operations after installing the August 2025 Windows security update.​​​​​​​

• [Device management]​​​​​​​ Fixed: An issue where the removable storage policy didn’t correctly block external devices such as USB flash drives.
• [File sharing] Fixed: This update addresses an issue where accessing files on a Server Message Block (SMB) share over Quick UDP Internet Connections (QUIC) might result in unexpected delays.
• [File server] This update enabled auditing SMB client compatibility for SMB Server signing as well as SMB Server EPA. This allows customers to assess their environment and identify any potential device or software incompatibility issues before deploying the hardening measures that are already supported by SMB Server. For detailed guidance, see CVE-2025-55234.

- [Input]

1. Fixed: This update fixes an issue where using Snap to organize desktop windows could cause the system to stop responding.
2. Fixed: An issue in Desktop Window Manager (uDWM) might cause the screen to stop responding during certain display operations.
3. Fixed: This update addresses an issue with the Chinese (Simplified) Input Method Editor (IME) where some extended characters appeared as empty boxes.

• [Performance] Improved: Added support for Certificate Revocation List (CRL) partitioning in Windows Certificate Authorities.

If you've already installed previous updates, your device will download and install only the new updates included in this package.

For more information about security vulnerabilities, see the Security Update Guide and the September 2025 Security Updates.