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Windows Insider

Build 27766

Build 27766: Windows Insider Experimental Channel, January 2025. Certain app blocks and Explorer crashes addressed

In short

Canary Channel Insiders get build 27766 with a fix for certain third-party apps blocked after a rollback, a fix for frequent Explorer crashes after a clean install or reset, and the main issues behind increased upgrade rollbacks addressed.

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

Build
27766
Review notes Additional details from the official release notes (2) Read notes
  • What changes Microsoft is not planning to release SDKs for 27xxx series builds for the time being.
  • Known issues On a new Copilot+ PC joining Canary from the Dev Channel, Release Preview Channel, or retail, Windows Hello PIN and biometric sign-in can be lost; users should be able to recreate the PIN by selecting “Set up my PIN.” Window borders or shadows may not appear when enabled, and animations may play when turned off.

The official sources are linked at the end of the page.

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

Fixes 3 changes

General

2 items
  • After rolling back from build 27764 to an earlier build, including after a failed upgrade, certain third-party apps can be used or installed without an incorrect policy blocking them.1
    Fixes an incorrectly enforced App Control for Business policy.
  • The main issues behind increased rollbacks when upgrading have been addressed. Error code 0xc190010 has multiple root causes, so upgrade issues might continue.2

Taskbar & System Tray

For: Some Insiders in the Canary Channel after a clean install or PC reset

  • Frequent crashes after a clean install or PC reset are fixed for some Canary Insiders.3
    Fixes an underlying issue causing frequent explorer.exe crashes.

Technical details

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

Data sheet

Released
2025-01-03
Type
Windows Insider build
VersionBuildChannel
— 27766 Experimental Channel

Security

No vulnerabilities are listed for this update.

Sources

Updated
Cited passages from Microsoft's official notes (3)
  1. 1. you would see an “Your organization used App Control for Business to block this app” dialog when attempting to use or install certain third-party apps on your PC due to an incorrect policy being enforced. blogs.windows.com
  2. 2. the main issues causing Insiders to experience an increase in rollbacks (with error code 0xc190010) when attempting to upgrade have been addressed. blogs.windows.com
  3. 3. Fixed an underlying issue which was causing some Insiders in Canary to experience frequent explorer.exe crashes after they clean installed or reset their PC. blogs.windows.com
Checked automatically: 8 of 8 checks passed, 3 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 5/5, clarity 4/5, completeness 3/5. 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