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Windows 11 Windows 11 Insider 26H2 Insider Preview, Experimental Channel
Windows Insider

Build 26340.9577

Build 26340.9577: Windows Insider Experimental Channel, September 2026. More Start activity and broader Narrator math reading support

In short

Build 26340.9577 for the Experimental Channel gradually adds more phone activity in Start, expands Narrator math reading, and brings other changes and a USB audio fix.

Does it affect you? Applies to: Devices enrolled in the Windows Insider Program in the Experimental Channel.

Build
26340.9577

This is a test build for people in the Windows Insider Program. Features in it can change, be removed, or never reach regular Windows releases.

What changes

Improvements 5 changes

Start menu

Gradual rollout

For: Insiders using the Start menu phone companion

  • The phone companion in Start shows more recent activity in a scrollable pane, so you can view more without leaving the Start menu.1

Settings

Gradual rollout

For: Insiders using Storage settings

  • The temporary files section under Settings > System > Storage has small visual refinements.2

Narrator

Gradual rollout 2 items
  • Math reading supports six languages: English (United States), English (United Kingdom), Traditional Chinese, Finnish, German, and Spanish.3
    Choose the language under Math reading settings in Narrator settings.
  • Narrator math reading works with supported web content in Edge and Chrome Stable.4
    Supported versions are Microsoft Edge Stable 153.0.4234.32 and later, and Chrome Stable 153.0.8010.18 and later.

Taskbar

Gradual rollout

For: Insiders using multiple monitors

  • Taskbar settings for multiple monitors retain their state better when monitors connect or disconnect.5

Fix 1 change

Audio

Gradual rollout
  • Certain USB audio devices, including some multichannel headsets, work correctly after installing the latest updates.6
    Fixes an issue affecting certain USB Audio Class 1.0 devices.

New feature 1 change

Settings

Gradual rollout

For: Insiders using Quick Settings

  • Energy Recommendations appear directly in Quick Settings, making them easier to find.7

Technical details

Data sheet · Security · Downloads · Components Click to collapse or expand

Data sheet

Released
2026-09-25
Type
Windows Insider build
VersionBuildChannel
— 26340.9577 Experimental Channel

Security

No vulnerabilities are listed for this update.

Sources

Updated
Cited passages from Microsoft's official notes (7)
  1. 1. Phone companion for the Start menu now shows more of your recent activity, with a scrollable side pane so you can view even more without leaving the Start menu. learn.microsoft.com
  2. 2. Made some small visual refinements to the design of the temporary files section under Settings > System > Storage. learn.microsoft.com
  3. 3. Narrator math reading now supports a total of six languages: English (United States), English (United Kingdom), Traditional Chinese, Finnish, German, and Spanish. learn.microsoft.com
  4. 4. Math reading is also now available for supported web content in Microsoft Edge Stable version 153.0.4234.32 and later and Chrome Stable version 153.0.8010.18 and later, making it easier to read and explore equations across more of the places where students and professionals work. learn.microsoft.com
  5. 5. Improved underlying state persistence of taskbar settings related to multiple monitors across monitor connections and disconnections. learn.microsoft.com
  6. 6. Fixed an issue affecting certain USB Audio Class 1.0 devices, including some multichannel audio headsets, that could prevent the device from working correctly after installing the latest updates. learn.microsoft.com
  7. 7. Windows Insiders will now see Energy Recommendations directly in Quick Settings, making it easier to discover and take actions that can help reduce energy consumption and improve device sustainability. learn.microsoft.com
Checked automatically: 8 of 8 checks passed, 7 quoted passages
  • Quotes found in the official pages: passed
  • Numbers found in the sources: passed
  • Vulnerabilities from the dossier only: passed
  • Links to allowed domains only: passed
  • Every official change covered: passed
  • Readable plain text: passed
  • Changes confirmed by the file list: passed
  • Sources agree: passed

A second AI read the text against the sources: correctness 4/5, clarity 5/5, completeness 5/5. How we work

Published by The Update Bureau. Written with AI from Microsoft's own documents, checked by rules and a second AI. How we work · Report a mistake