KB5070312 for Windows 11: Full Breakdown of Fixes, Changes & Whether You Should Install It

Keeping an operating system healthy isn’t just about big feature updates. Sometimes, the most valuable patches are small, targeted fixes that improve everyday reliability. KB5070312, a non-security preview update for Windows 11 version 23H2, is one of those updates: quiet, focused, and important if you care about stability.

Released on November 20, 2025, KB5070312 upgrades devices to OS Build 22631.6276 and comes bundled with the servicing stack update (SSU) KB5071963. Instead of flashy features, it improves core components users rely on daily—from File Explorer responsiveness to enterprise-class Group Policy behavior.

KB5070312 Overview and Release Context

Microsoft now ships Windows with one major feature update per year, followed by cumulative updates that refine stability and security. KB5070312 arrives late in the lifecycle of Windows 11 23H2, especially since:

• 23H2 Home and Pro editions have already reached end of servicing (Nov. 2025).
• Enterprise, Education, IoT Enterprise, and multi-session editions remain supported until Nov. 10, 2026.

This update targets the supported business editions of 23H2, improving reliability while preparing machines for upcoming maintenance needs.

Important Notice: Secure Boot Certificates Expire in 2026

Hidden inside the update documentation is a major alert: current Windows Secure Boot certificates begin expiring in June 2026.

Devices without updated firmware and trusted certificate chains may:

• Fail to boot securely
• Lose the ability to validate boot components
• Be unable to receive future Secure Boot-related protections

⚠️ Organizations must plan updates across firmware, certificate stores, and Windows deployments. Microsoft provides technical guidance in its Secure Boot expiration documentation, and OEM vendors will distribute required firmware updates.

Upcoming End-of-Support Deadlines for Windows 11

💡 If you’re on 23H2 Home or Pro, upgrading to Windows 11 24H2 or 25H2 is more urgent than installing preview updates like KB5070312.

What KB5070312 Fixes

KB5070312 is small but impactful. It addresses four common issues plus a servicing reliability update:

Highlight Fix: File Explorer Clicks Not Registering

One of the most visible bugs fixed involves File Explorer ignoring mouse actions—forcing users to restart the application. This update corrects the issue, reducing support calls in enterprise deployments and improving daily usability.

Quick tip: If the problem persists, restarting explorer.exe through Task Manager remains a reliable workaround—useful for diagnosing third-party shell extensions.

.tar Extraction and Chinese Filenames

Systems previously failed to extract archives if file/folder names exceeded a threshold of 34 commonly used Chinese characters. This patch ensures Windows handles longer Chinese filenames correctly, restoring interoperability with macOS and Linux workflows.

Group Policy Fix for Azure Virtual Desktop

Administrators managing Windows 11 Enterprise multi-session environments (such as AVD) can once again rely on the HideRecommendedSection policy. It now properly disables Start menu recommendations for shared or controlled desktop experiences.

Servicing Stack Update (KB5071963): Why It Matters

The servicing stack is the update engine of Windows. A damaged or outdated servicing stack can cause:

• Update install loops
• Rollbacks during reboot
• Unclear error messages and failed deployments

This SSU is permanent—once installed, it cannot be removed. If you need to roll back the LCU portion, Microsoft recommends using DISM, not wusa.exe.

How to Download KB5070312

Should You Install KB5070312?

Install it if:
✔ You experience File Explorer freezes
✔ You rely on .tar archives with Chinese filenames
✔ You manage Azure Virtual Desktop or multi-session desktops
✔ You want the latest servicing stack for future updates

Skip it (for now) if:
🚫 Your systems are stable and not affected by these issues
🚫 You prefer to wait for fixes to roll into the next security (Patch Tuesday) update

For Home and Pro devices already past support, upgrading Windows 11 is far more important than installing this update.

Final Takeaway

KB5070312 is not a flashy release, but it quietly sharpens Windows 11 for everyday use—especially in managed business environments. While consumers on unsupported builds should prioritize moving to Windows 11 24H2 or 25H2, enterprises still within the service window benefit from piloting this update and preparing for bigger milestones ahead, such as Secure Boot certificate expiration in 2026.