Microsoft Rolls Out KB5079391 Preview Update for Windows 11
Microsoft released the KB5079391 preview cumulative update on March 27, 2026, targeting Windows 11 versions 24H2 and 25H2. This optional preview update delivers 29 distinct improvements across core Windows functionality, with particular focus on Smart App Control enhancements and display system optimizations.
The update represents Microsoft's continued refinement of Windows 11's security and user experience features. Smart App Control, which was introduced as a security feature to help protect against malicious applications, receives significant improvements in this release. The feature uses machine learning and cloud-based intelligence to evaluate application trustworthiness before execution, and these updates enhance its accuracy and reduce false positives that have frustrated enterprise users.
Display improvements form another major component of KB5079391, addressing compatibility issues with modern high-resolution monitors and multi-display configurations. These changes specifically target problems that IT administrators have reported with scaling inconsistencies across different display types and resolutions, particularly in enterprise environments with mixed hardware configurations.
The preview update follows Microsoft's established pattern of releasing optional updates in the fourth week of each month, allowing organizations to test changes before they become mandatory in the following month's Patch Tuesday release. This approach gives IT departments crucial time to evaluate compatibility with their existing software stack and hardware configurations.
Related: Microsoft confirms ongoing Windows 11 File Explorer flash
Related: Windows 11 March Optional Update Hits Release Preview
Related: Microsoft Targets File Explorer Performance Issues in
Related: Windows 11 Gets Indefinite Update Deferral Option
Related: Microsoft Overhauls Windows 11 to Match macOS and Linux
According to Microsoft Support documentation, the update includes fixes for several underlying system components that weren't addressed in previous monthly releases. These improvements span across Windows Update mechanisms, system file integrity checks, and background service optimizations that should improve overall system stability.
Windows 11 24H2 and 25H2 Users Can Access New Features
The KB5079391 update specifically targets devices running Windows 11 version 24H2 (build 26100) and the newer 25H2 release (build 26200 and later). Organizations that have deployed these versions across their infrastructure can immediately benefit from the Smart App Control improvements, which are particularly valuable for environments that rely on application whitelisting and security policies.
Enterprise customers using Windows 11 Enterprise and Education editions will see the most significant impact from the display improvements, especially those managing mixed hardware environments with various monitor types and resolutions. The update addresses scaling issues that have affected productivity in organizations with hot-desking arrangements or shared workstation setups.
Home users running Windows 11 Pro or Home editions on 24H2 or 25H2 builds will also receive the update through Windows Update's optional preview channel. However, the most noticeable improvements will be for users with multi-monitor setups or high-DPI displays who have experienced scaling inconsistencies or display detection problems.
The update doesn't affect Windows 11 22H2 or 23H2 installations, as Microsoft maintains separate update channels for different feature releases. Organizations still running older Windows 11 versions should plan their upgrade path to access these improvements, particularly if they're experiencing Smart App Control limitations or display-related issues in their current deployments.
How to Install KB5079391 and Configure New Features
IT administrators can deploy KB5079391 through multiple channels, starting with Windows Update for Business or Windows Server Update Services (WSUS) for enterprise environments. The update appears in the optional preview section of Windows Update, requiring manual selection for installation. Organizations using Microsoft Intune can push the update through their device management policies, allowing for controlled rollout across different user groups or device collections.
For manual installation, administrators can access the update through Settings > Windows Update > Advanced options > Optional updates. The installation process requires a system restart, and Microsoft recommends scheduling the deployment during maintenance windows to minimize user disruption. The update download size varies between 150-300 MB depending on the current system configuration and previously installed updates.
Smart App Control improvements become active immediately after installation, but administrators should review their existing application policies to ensure compatibility with the enhanced detection mechanisms. The updated Smart App Control system may flag previously trusted applications if they lack proper code signing or have been modified since initial deployment. IT teams should prepare to whitelist legitimate business applications that might trigger new security warnings.
Display improvements require no additional configuration for most users, but organizations with complex multi-monitor setups should test scaling behavior across different display configurations. The update includes new registry keys for fine-tuning display scaling behavior, accessible through Group Policy or direct registry modification for advanced customization needs. Microsoft provides detailed configuration guidance in the official KB5079391 documentation for organizations requiring specific display management policies.
