Microsoft Support, updated Sep 30, 2026 KB5055523 security change Insider build 26340.9882

Windows Hello Not Working in Low Light? Windows 11 Brightness & PIN Fix

If Windows Hello face sign-in works in daylight but fails in a dim room, the cause is a security change Microsoft made with KB5055523. Use the diagnostic below to find your cause, then see what Microsoft has confirmed about the low-light brightness toggle (returning from November 2026) and the PIN box beside face sign-in (in testing).

Updated: November 8, 2026 Verified against: Microsoft low-light sign-in, KB5055523 notes & Insider build 26340.9882 Related: Windows 11 26H2 Guide

Why Low-Light Sign-In Stopped Working Microsoft’s KB5055523 notes (April 8, 2025, Windows 11 24H2) say that after this or a later update, Windows Hello face sign-in requires color cameras to see a visible face, tied to CVE-2025-26644. Low light can leave the color camera unable to see you even when the infrared camera detects your face. A privacy shutter or keyboard camera key can also interrupt sign-in, and depending on your device it may disable the infrared camera too.

Fix 1: Low-Light Brightness Toggle Microsoft says the setting is off by default, was removed for a short while, and is scheduled to reappear starting November 2026. When it reaches your PC, it briefly brightens the screen to light your face, then restores your brightness (Microsoft Support).

Fix 2: PIN Box Beside Face Sign-In Microsoft is testing a lock screen where you can type your PIN without waiting for face or fingerprint to finish. It is in Insider Experimental build 26340.9882 (Nov 6, 2026). No stable-release date has been announced (Windows Latest).

November 6 Insider update: Microsoft’s release notes also list the low-light brightness setting in Windows 11 Insider Experimental build 28120.3454 (26H1), rolling out to Insiders in stages. That is separate from build 26340.9882 (26H2), which tests the PIN-entry change. Neither build confirms a general release date. See Microsoft’s 26H1 release notes.

Windows Hello Low-Light & Sign-In Diagnostic

How it works: a web page cannot inspect your camera or Windows Update status, so answer five quick checks and it points you to the matching Microsoft guidance.

1. Does your PC have a Windows Hello (infrared) camera?

2. Is the camera privacy shutter or slider open?

3. Does face sign-in work in a normally lit room?

4. Under Settings → Accounts → Sign-in options → Facial recognition, do you see the brightness toggle?

5. On the lock screen, is a PIN box shown while face recognition runs?

Watch: How to Improve Windows Hello Face Recognition (NinjaOne)

How To Improve Windows Hello Face Recognition In Windows 10 And 11

NinjaOne IT Video Hub · published September 25, 2025

Clean the lens and use a well-lit workspace
Update drivers and Windows, then use Improve recognition in Sign-in options
Scan with and without glasses and in different lighting

This video predates the low-light toggle’s return and the PIN-box change, so use the sections on this page for those.

Video page and transcript →

What Is Confirmed, What Is Still Testing

Item	Status	Source
Color camera must see a visible face	Live since KB5055523 (April 8, 2025, Windows 11 24H2) and later updates.	Microsoft KB5055523
Low-light brightness toggle	Off by default. Removed briefly; scheduled to reappear starting November 2026. Also listed in Insider Experimental 26H1 build 28120.3454 (Nov 6, 2026).	Microsoft Support, Insider notes
How the brightness boost behaves	Only when the IR camera sees your face but the color camera lacks light. Brightness returns afterward. PIN or fingerprint still works if it fails.	Microsoft Support
PIN box beside face / fingerprint	Testing in Insider Experimental build 26340.9882 (Nov 6, 2026). After a restart, Windows still asks for your PIN first. No stable date announced.	Microsoft Insider notes, Windows Latest
Disabling the color camera in Device Manager	Not a Microsoft-documented fix. Windows Latest’s writer tried it but does not recommend it, and said some readers found it didn’t help.	Windows Latest

Why we don’t recommend disabling your color camera: KB5055523 added the color-camera check for security, so turning that camera off works against it. You also lose the webcam for Teams, Zoom and browser calls until you turn it back on. Use Microsoft’s brightness toggle, your PIN, or a fingerprint reader instead.

Step-by-Step: Turn On Low-Light Sign-In in Windows 11

Open Start → Settings → Accounts → Sign-in options.
Expand Facial recognition (Windows Hello).
Turn on Automatically adjust screen brightness during face recognition. It is off by default, so it will not work until you switch it on.
If you don’t see the toggle, it hasn’t reached your PC yet. Microsoft says it returns starting November 2026, so check Settings → Windows Update over the coming weeks.

If face sign-in still fails after the brightness boost, Microsoft says you can sign in with your PIN or fingerprint. To retrain recognition, use Improve recognition in the same section, and see Microsoft’s guide on why Windows Hello didn’t recognize you.

Work or school PC? NinjaOne notes that poor lighting can cause problems, especially when Enhanced anti-spoofing is enabled in a managed environment. If recognition keeps failing in different lighting, ask your IT team about that policy.

Face sign-in needs a Hello-compatible camera, per Configure Windows Hello. A standard webcam alone won’t work.

Frequently Asked Questions

Why is Windows Hello not working in low light on Windows 11?

Microsoft’s KB5055523 release notes say that after that update or a later one, Windows Hello face sign-in requires the color camera to see a visible face. In a dark room the color camera can’t, even if the infrared sensor works. A covered lens or camera privacy key can also interrupt sign-in.

How do I turn on the low-light brightness setting?

Go to Settings, Accounts, Sign-in options, expand Facial recognition (Windows Hello), and turn on “Automatically adjust screen brightness during face recognition.” Microsoft says it is off by default and scheduled to reappear starting November 2026.

Why do I have to wait before typing my PIN?

Today Windows waits for face or fingerprint to finish unless you tap Sign-in options. Microsoft is testing a change in Insider Experimental build 26340.9882 that lets you use whichever method works first. No stable-release date has been announced.

Does the KB5055523 change apply to my PC?

Microsoft’s KB5055523 page is for Windows 11 version 24H2 and says the requirement applies after installing it or a later Windows update. Check your update history if you are unsure.

Should I disable my color camera in Device Manager?

We don’t recommend it. It isn’t a Microsoft-documented fix, it works against the security check added in KB5055523, and it turns off your webcam for video calls until you re-enable it.

Will Windows still ask for my PIN after a restart?

Yes. Microsoft’s Insider notes say that after a restart you will need your PIN first, and biometrics work as usual afterward.

Sources

Related Windows 11 Updates & Troubleshooting Guides

Windows 11 8GB RAM Boost: 26H2 Build & Update Check See Microsoft’s official memory compression, Edge & Teams optimizations Windows 11 KB5127936: New Right-Click Menu & How to Enable Check build numbers and File Explorer context menu improvements Move Windows 11 Taskbar to Top, Left or Right (2026) Complete guide to Windows 11 taskbar positioning and settings Office 2021 End of Support: Will Word and Excel Stop Working? What happens to standalone Office licenses and security patches