Error installing windows 11 insider preview 29639.1000 (rs_prerelease)

Question

Error installing windows 11 insider preview 29639.1000 (rs_prerelease)

Ihsan Tanjung 5

More than 10 times I have tried to update my laptop which is always failed. I don't understand at all.

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2 answers

Your answer

Answer 1

Johnny55 5,150 Volunteer Moderator

Hello Ihsan,

Please download the ISO image of 29639 from here and do a repair install.

https://www.microsoft.com/en-us/software-download/windowsinsiderpreviewiso

Mount the image file by right clicking, and run setup.exe within Windows.

Regards,

Johnny

Antonio Giovanni Colombo 0 Reputation points

2026-08-11T20:19:16.66+00:00

It did not work. The ISO install gave me back my old build (10.0.29617.1000). I am suspending updates for 8 days, hoping that the next build solves the problem.
BryceSor 5,500 Reputation points Volunteer Moderator

2026-08-11T22:31:43.7+00:00

So you are saying the update won't install again or it's not showing in WU to install?
Antonio Giovanni Colombo 0 Reputation points

2026-08-12T05:49:28.5333333+00:00

The update in itself was executed just fine, and concluded on its own that the upgrade could not be made, i.i., it gave me back my previous build. A gigantic NO-OP.

Answer 2

For repeated Windows 11 Insider Preview install failures, start with the standard upgrade fixes that address the most common causes:

Disconnect nonessential external hardware. Remove USB drives, external disks, docks, printers, scanners, speakers, and similar devices before retrying the update.
Make sure Windows is fully updated. Go to Start > Settings > Windows Update and install all available updates, including driver updates.
Check free space. For upgrade scenarios, Windows requires at least 16 GB free for 32-bit or 20 GB free for 64-bit.
Update or remove problematic drivers. Errors beginning with 0xC1900101 are usually driver-related. Open Device Manager and look for devices with a yellow exclamation mark. For any affected device, use Update Driver Software or Uninstall.
Remove third-party antivirus or security software temporarily. This can block upgrades. Make sure reinstall information or product keys are available before uninstalling.
Run Windows Update multiple times. Install everything offered, including hardware and third-party driver updates. The Windows Update Troubleshooter can also help fix update errors.
Repair the hard drive and system files. These commands require administrator permissions.
- Open Command Prompt as administrator and run: chkdsk /f C:
- Then run: DISM.exe /Online /Cleanup-image /Restorehealth
Warning: these are advanced command-line steps and require administrator access.
If update files may be corrupted, reset Windows Update components. Open Command Prompt as administrator and run these commands one at a time: net stop bits net stop wuauserv ren %systemroot%\softwaredistribution softwaredistribution.bak ren %systemroot%\system32\catroot2 catroot2.bak net start bits net start wuauserv Then restart the PC.
If the failure message shows a specific error code, use that code to narrow the fix. In Windows 11, the failed update code can be found in Start > Settings > Windows Update > Update history.
If the same Insider build keeps failing after these steps, note the exact error code from Update history and use that to target the issue further.