Each month, the team at Readiness analyzes the latest Patch Tuesday updates from Microsoft and provides detailed, actionable testing guidance. This month’s release includes a high-risk update to the Desktop Window Manager alongside security hardening for network file sharing and deployment services. Organizations should prioritize visual and personalization testing given the DWM changes.
Graphics & Display
The Desktop Window Manager received updates this month, marked as high risk by Microsoft. These changes affect how Windows renders visual elements.
Test Scenarios:
- Apply theme changes and verify accent colors render correctly on window borders
- Test taskbar color customization and transparency settings
- Validate DirectComposition-based applications render without artifacts
- Switch between light and dark modes and confirm UI consistency
- Test multi-monitor configurations with different DPI scaling
Touch & Pen Input
Windows Ink components received updates affecting touch and stylus input handling.
Test Scenarios:
- Test pen input in applications like OneNote, Whiteboard, and drawing tools
- Validate touch gestures respond accurately across the display
- Verify pressure sensitivity functions correctly with supported styluses
- Test palm rejection during pen input sessions
Network File Sharing
SMB (Server Message Block) components received security updates affecting both modern and legacy protocols.
Test Scenarios:
- Access SMB shares configured with mandatory signing and verify connectivity
- Test encrypted SMB connections between clients and servers
- Validate SMB share access across domain trust boundaries
- If SMBv1 is still required in your environment, test legacy share access with signing enabled
Windows Deployment Services
Security hardening changes affect unattended OS deployment scenarios. New registry controls modify default behavior. Testing should cover the following areas:
- Perform network-based OS deployments using existing unattended configurations
- Verify handsfree deployment workflows complete successfully
- Review event logs for new security-related warnings during deployment
- Test deployment scenarios with various security configurations
Window Management
Core window management components received updates affecting application behavior.
Test Scenarios:
- Minimize, maximize, and restore applications to verify correct behavior
- Move and resize windows, confirming smooth transitions
- Close applications and reopen to verify window position persistence
- Test window operations in Remote Desktop sessions
Office Applications
Security updates address vulnerabilities in Excel, Word, and SharePoint Server components.
Test Scenarios:
- Open and edit complex Excel workbooks with formulas and macros
- Test Word document formatting and embedded object handling
- Validate SharePoint document library operations and co-authoring
- Verify Office add-ins continue to function after patching
Focus testing efforts on the Desktop Window Manager changes first, as Microsoft has flagged these as high risk. Visual rendering issues can significantly impact user experience and productivity. Secondary priority should be given to SMB testing if your environment relies heavily on network file shares with signing or encryption requirements.
SQL Server 2022 and 2025 also received GDR updates this month. If you manage SQL Server environments, follow your standard patching and validation procedures for these cumulative updates.
