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Windows 11 Windows 11 Insider 26H1 Insider Preview, Beta Channel
Windows Insider

Build 28020.3112

Build 28020.3112: Windows Insider Beta Channel, September 2026. Plan9 folder access fixed in some virtual machine apps

In short

Beta Channel Insiders receive a gradual fix for Plan9 folder sharing in some applications that use HCS-managed virtual machines, plus a small set of general improvements.

Does it affect you? Applies to: Devices enrolled in the Beta Channel (26H1) of the Windows Insider Program.

Build
28020.3112

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

Fix 1 change

Hyper-V

Gradual rollout

For: Users of some applications that use HCS-managed virtual machines

  • In some applications that use managed virtual machines, shared Windows folders now appear in the Linux guest and can be opened.1
    Fixes Plan9 host-folder sharing for some applications using HCS-managed virtual machines.

Improvement 1 change

General improvements and fixes

Gradual rollout

For: Insiders running this build

  • A small set of general improvements and fixes improves the experience on PCs running this build.2

Technical details

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

Data sheet

Released
2026-09-25
Type
Windows Insider build
VersionBuildChannel
— 28020.3112 Beta Channel

Security

No vulnerabilities are listed for this update.

Sources

Updated
Cited passages from Microsoft's official notes (2)
  1. 1. Fixed an issue where some applications that used HCS-managed virtual machines experienced issues when sharing host folders with Linux VMs using Plan9. learn.microsoft.com
  2. 2. This update includes a small set of general improvements and fixes that improve the overall experience for Insiders running this build on their PCs. learn.microsoft.com
Checked automatically: 8 of 8 checks passed, 2 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 4/5, 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