KB5073724 — January 2026 Cumulative Update for Windows 10

Overview

KB5073724 is a comprehensive cumulative update released on January 13, 2026, for Windows 10 systems running version 21H2 and 22H2. This update brings affected systems to builds 19045.6809 and 19044.6809 respectively, incorporating critical security fixes, system stability improvements, and compatibility enhancements.

Affected Systems

This update applies to the following Windows 10 versions:

All editions of Windows 10 are affected, including Home, Pro, Pro for Workstations, Enterprise, Education, and IoT Enterprise editions.

Security Improvements

This cumulative update includes multiple security enhancements designed to protect Windows 10 systems from emerging threats. The security fixes address vulnerabilities in core system components, including the Windows kernel, system services, and network stack. These improvements help prevent potential privilege escalation attacks and strengthen overall system security posture.

System Performance Enhancements

Beyond security fixes, KB5073724 includes several performance optimizations that improve system responsiveness and reduce resource consumption. Memory management has been enhanced to prevent memory leaks in certain scenarios, and system service efficiency has been improved to reduce CPU usage during routine operations.

Compatibility Updates

The update addresses compatibility issues with newer hardware components and software applications. Driver support has been enhanced for various device categories, including USB devices, display adapters, and audio hardware. These improvements ensure better compatibility with modern hardware while maintaining support for legacy devices.

Network and Connectivity Fixes

Network-related improvements in this update address several connectivity issues that could affect file sharing, network printing, and domain authentication. The SMB protocol implementation has been updated to improve reliability and performance, particularly in enterprise environments with complex network configurations.

Installation Requirements

Before installing KB5073724, ensure your system meets the following requirements:

• At least 2 GB of free disk space on the system drive
• Active internet connection for download (if installing via Windows Update)
• Administrative privileges for installation
• No pending restart requirements from previous updates

Post-Installation Verification

After successful installation, verify the update by checking the system build number:

Get-ComputerInfo | Select-Object WindowsProductName, WindowsVersion, TotalPhysicalMemory

The build number should reflect 19045.6809 for Windows 10 22H2 or 19044.6809 for Windows 10 21H2.

Enterprise Deployment Considerations

For enterprise environments, Microsoft recommends testing KB5073724 in a controlled environment before widespread deployment. The update can be deployed through existing patch management infrastructure, including WSUS, SCCM, or cloud-based solutions like Microsoft Intune.

Organizations should also review their third-party software compatibility, particularly security solutions and line-of-business applications, to ensure continued functionality after the update installation.