KB5124058


Microsoft has released cumulative update KB5124058 (Build 26340.9354) for Windows 11 version 26H2, intended for insiders on the Experimental channel. This build brings a number of significant improvements, including reading of mathematical formulas by Narrator, separate magnification for each monitor in Magnifier, redesigned sound settings, and a device information card on the main Settings page. Changes are being rolled out to insiders gradually, so some features may not appear for everyone at the same time.

Known issues: Microsoft is working on fixing an issue where mouse cursor appearance settings are applied incorrectly. Work is also underway to fix an issue where desktop background settings are not saved after a restart.

To install update KB5124058, go to Settings > Windows Update and click "Check for updates". A computer restart is required to complete the installation. The update is intended for insiders on the Experimental channel, and to receive it you must be a member of the Windows Insider Program with the corresponding update channel.

Feature / Change Performance Impact Optimization PC Speed Gaming Optimization
Continue from phone (resume card with browser options) ⚪ No impact 🟢 High (streamlined workflow) ⚪ No impact ⚪ No impact
Device information card on main Settings page ⚪ No impact 🟡 Medium (faster access to system info) ⚪ No impact ⚪ No impact
Redesigned Privacy & security page ⚪ No impact 🟢 High (grouped permissions, fewer clicks) ⚪ No impact ⚪ No impact
Clearer parental control block messages ⚪ No impact 🟡 Medium (better UX clarity) ⚪ No impact ⚪ No impact
Improved taskbar preview animations 🟢 Slight improvement (smoother rendering) 🟡 Medium 🟢 Slight improvement 🟡 Low (minor UI smoothness)
Consistent file info order in search results ⚪ No impact 🟡 Medium (easier scanning) ⚪ No impact ⚪ No impact
Narrator math formula reading ⚪ No impact 🟢 High (accessibility efficiency) ⚪ No impact ⚪ No impact
Magnifier per-monitor zoom and view pinning 🟡 Low (slight rendering overhead) 🟢 High (better multi-monitor workflow) 🟡 Low ⚪ No impact
Sound settings: activity indicators, hardware acceleration, adaptive volume 🟢 Slight improvement (HW acceleration reduces CPU load) 🟢 High (all audio controls in one place) 🟡 Low (depending on device) 🟡 Low (better audio management during games)
Ebrima font supports Garay and Beria Erfe scripts ⚪ No impact 🟡 Medium (fewer font fallbacks) ⚪ No impact ⚪ No impact
Adlam font refinements ⚪ No impact 🟡 Low (better text clarity) ⚪ No impact ⚪ No impact
Print management UI temporarily removed ⚪ No impact 🔴 Low (temporary regression) ⚪ No impact ⚪ No impact
Notification hints saved in notification center ⚪ No impact 🟡 Medium (easier retrieval) ⚪ No impact ⚪ No impact
Fixed mouse cursor direction on portrait monitors 🟢 Slight improvement (correct input handling) 🟢 High (usability fix) 🟡 Low 🟡 Low (better for portrait setups)
Administrator protection UAC prompt fix ⚪ No impact 🟡 Medium (security reliability) ⚪ No impact ⚪ No impact
Assisted Setup optional step at first launch 🟡 Low (slight initial setup overhead) 🟢 High (faster PC readiness) 🟡 Low (setup time) ⚪ No impact
Fixed SYSTEM_SERVICE_EXCEPTION blue screen 🟢 High (stability fix) 🟢 High (crash prevention) 🟢 High (fewer interruptions) 🟢 Medium (more stable gaming sessions)

Find and Change Settings

Setting Where to find How to change
Device Information Card Settings > System > About Open Settings and go to the main page to view the device information card. To see detailed system information, click the card or navigate to Settings > System > About. The card is available when signed in with a Microsoft account.
Privacy and Security Permissions Settings > Privacy & securityOpen Settings > Privacy & security to view grouped camera, microphone, and location permissions. Toggle each permission on or off directly on the page to allow or block app access.
Family Safety Block Messages Settings > Accounts > Family When an app is blocked by parental controls due to age restrictions, the message now appears with clearer wording. To adjust restrictions, open Settings > Accounts > Family and manage family group settings.
Taskbar Preview Animations Settings > Personalization > Taskbar Improved preview animations are enabled automatically. To adjust taskbar behavior, open Settings > Personalization > Taskbar and change the available options.
File Explorer Search Results Layout File Explorer > Search Search results display name, location, and date in a consistent order automatically. No additional configuration is required.
Narrator Math Formula Reading Settings > Accessibility > Narrator Turn on Narrator with Win + Ctrl + Enter. To navigate formula parts, press Narrator key + Alt + N, then use arrow keys. Exit the mode with Esc. Configure reading style in Settings > Accessibility > Narrator under mathematical formula reading.
Magnifier Per-Monitor Zoom Settings > Accessibility > Magnifier Use Win + + or Win + - over a monitor to change its magnification. Pin the view with Ctrl + Win + K, unpin with the same combination or Win + Esc. Change the pin shortcut to Ctrl + Alt + P in Magnifier settings.
Sound Device Hardware Acceleration Settings > System > Sound > Device properties Open Settings > System > Sound, select a device, and open its additional settings to enable hardware acceleration or configure exclusive mode.
Adaptive Volume During Conversations Settings > System > Sound Open Settings > System > Sound and find the adaptive volume option to lower other sounds during a call. Toggle it on or off.
Default Communication Device Settings > System > Sound Open Settings > System > Sound and use the communication device selector. If already selected, the item remains visible but inactive.
Mono Sound Warning Settings > System > Sound Open Settings > System > Sound and enable or disable mono sound. A warning appears when enabled, indicating some settings do not apply.
All Sound Devices Page Settings > System > Sound > All sound devices Open Settings > System > Sound > All sound devices to select default devices, filter by input or output, and show or hide disabled or disconnected devices.
Device Connector Information Settings > System > Sound > Device properties Open the properties page of an input or output device to view connector information where applicable.
Fonts Garay and Beria Erfe Settings > Personalization > Fonts Install or select the Ebrima font to use Garay and Beria Erfe scripts. Open Settings > Personalization > Fonts to manage installed fonts.
Print Management Interface Settings > Bluetooth & devices > Printers & scanners The updated print management interface is temporarily removed. Use the previous print management tools available in the same section.
Notification Center Hints Notification Center Hints from notifications are saved automatically after being closed or disappearing. Open the notification center to find them later.
Mouse Cursor Direction on Portrait Monitors Settings > Bluetooth & devices > Mouse The issue is fixed automatically. If needed, adjust mouse settings in Settings > Bluetooth & devices > Mouse.
Administrator Protection UAC Prompt Settings > Privacy & security > Security The issue is fixed automatically. Administrator protection settings can be managed in Settings > Privacy & security > Security.
Assisted Setup at First Launch Initial Windows Setup At the end of initial setup, an optional Assisted Setup step appears. Follow the prompts to install apps and personalize the device, or skip to go to the desktop.
General Stability Windows Update The SYSTEM_SERVICE_EXCEPTION issue is fixed automatically. Install the latest update via Settings > Windows Update.

Official announcement on the Microsoft website.

The last 10 Windows updates:

Update Build Version Windows Channel Date
KB5124010 26300.9539 26H2 Windows 11 Preview 2026-09-10
KB5125726 28120.2912 26H1 Windows 11 Experimental 2026-09-08
KB5124058 26340.9354 26H2 Windows 11 Experimental 2026-09-08
KB5124061 26220.9343 25H2 Windows 11 Beta 2026-09-08
KB5124059 28020.2904 26H1 Windows 11 Beta 2026-09-08
KB5122880 22631.7582 23H2 Windows 11 Stable 2026-09-08
KB5122878 19045.7725 22H2 (ESU) Windows 10 Stable 2026-09-08
KB5124012 28000.2954 26H1 Windows 11 Stable 2026-09-08
KB5124008 26300.9445 26H2 Windows 11 Stable 2026-09-08
KB5121157 28020.2818 26H1 Windows 11 Beta 2026-08-31