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Windows Insider

Build 29661.1000

Build 29661.1000: Windows Insider Experimental Channel, September 2026. IAKerb enabled by default; cursor and update fixes

In short

Experimental Channel Insiders get IAKerb enabled by default, fixes for mouse cursor and pointer-speed problems, and a fix for Windows Update error 0x80070005.

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

Build
29661.1000

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 4 changes

Input

Gradual rollout 3 items
  • The mouse cursor no longer repeatedly blinks for some Insiders.1
  • The mouse cursor is visible again in certain apps.2
  • The mouse pointer speed option in Settings works again.3

Windows Update

Gradual rollout
  • Some Insiders can update to the latest builds without encountering error 0x80070005.4

Improvements 2 changes

General

Gradual rollout
  • A small set of general improvements and fixes improves the experience for Insiders running this build.5

Kerberos enhancements

Gradual rollout

For: Windows client users

  • Windows authentication can work when the PC cannot connect directly to a domain controller.6
    IAKerb is enabled by default for Windows client. This Kerberos extension supports authentication when a direct connection to a domain controller is unavailable and helps reduce reliance on NTLM.

Technical details

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

Data sheet

Released
2026-09-08
Type
Windows Insider build
VersionBuildChannel
— 29661.1000 Experimental Channel

Security

No vulnerabilities are listed for this update.

Sources

Updated
Cited passages from Microsoft's official notes (6)
  1. 1. Fixed an issue in the latest builds that caused the mouse cursor to get into a state where it blinked repeatedly for some Insiders. learn.microsoft.com
  2. 2. Fixed an issue in the latest builds that caused the mouse cursor not to be visible in certain apps. learn.microsoft.com
  3. 3. Fixed an issue in the latest builds where the mouse pointer speed option in Settings didn't work. learn.microsoft.com
  4. 4. Fixed an issue causing some Insiders to be unable to update to the latest builds and see error 0x80070005. learn.microsoft.com
  5. 5. 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
  6. 6. IAKerb is now enabled by default for Windows client. learn.microsoft.com
Checked automatically: 8 of 8 checks passed, 6 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 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