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Does the Windows 11 December patch actually fix the File Explorer white flash glitch?
Windows 11 KB5072033 Advisory: Critical Analysis of December 2025 Patch
Microsoft has deployed update KB5072033, the final Patch Tuesday release of 2025. While our analysis indicates superior stability compared to prior releases, specific technical conflicts persist. Users should be aware of two primary issues affecting the visual interface and development workflows before deployment.
File Explorer Graphical Glitches Persist
The December update attempts to resolve high-contrast rendering issues within File Explorer, specifically the “white flash” occurring in Dark Mode. Microsoft successfully mitigated the flashing that occurred when maximizing the window or navigating to the Home and Gallery tabs.
However, the remediation is incomplete. Users will still encounter a brief, jarring white flash when opening a new tab. This occurs whether utilizing the Ctrl+T shortcut or clicking the ‘+’ interface icon. The window forces a rapid re-render the moment the new tab initializes. This behavior remains consistent across system reboots, indicating a rendering pipeline issue rather than a temporary cache glitch.
Critical WSL Connectivity Failure with VPNs
A more severe functional defect impacts developers using the Windows Subsystem for Linux (WSL). Update KB5072033, along with all updates released post-October 28, introduces a breaking change for specific networking configurations.
The failure occurs exclusively when two conditions are met:
- Mirrored Networking Mode is enabled within WSL.
- A third-party enterprise VPN (specifically Cisco Secure Client or OpenVPN) is active.
Under these conditions, the Linux subsystem loses external connectivity. The terminal returns a “No route to host” error, severing access to external repositories like GitHub.
Technical Root Cause
Microsoft documentation confirms the failure stems from the VPN application’s virtual interface. The interface fails to respond to Address Resolution Protocol (ARP) requests generated by the WSL mirrored network. Consequently, the subsystem cannot resolve the network path.
Advisory and Timeline
This networking issue predominantly affects Enterprise environments and developers. Standard consumers running Windows Home or Pro editions without specialized WSL networking configurations likely remain unaffected.
Microsoft engineers are currently investigating a permanent resolution. However, a patch is not expected until the next major cycle on January 13, 2026. Until then, affected users may need to disable mirrored networking or temporarily roll back the update to maintain VPN compatibility within WSL.