Microsoft Releases Windows Server vNext Preview Build 26491

Microsoft today released Windows Server vNext Preview Build 26491 for Insiders. This build is available for Datacenter and Standard editions, as well as the Azure Edition for VM evaluation. The preview retains the Windows Server 2025 branding.

Note: If you signed up for Server Flighting, this build should arrive automatically.

What’s New in Build 26491

Windows Server insiders can now use flighting to upgrade via Windows Update, skipping manual ISO installs. This in-place upgrade works for Desktop Experience builds, while the traditional ISO method remains available.

Updates must still be checked manually, keeping admins in control. Microsoft plans to expand flight over time and welcomes feedback. Next up, the Feedback Hub app is now available for Server Desktop. It should auto-update, but you can manually check for updates in the app’s settings if necessary.

Known Issue

Some flights may incorrectly label this build as Windows 11. You can simply ignore the label; the installed package is the correct Windows Server update. Microsoft plans to fix this in a future release.

Downloads and Availability

• ISO: Available in 18 languages for LTSC Preview
• VHDX: English only
• Azure Edition: ISO and VHDX, English only
• Certain downloads may be restricted in some regions (e.g., Russia)

Microsoft says the preview build expires on September 15, 2026. It also mentions some Preview Keys, which are valid for the build only. Check them below:

• Server Standard: MFY9F-XBN2F-TYFMP-CCV49-RMYVH
• Datacenter: 2KNJJ-33Y9H-2GXGX-KMQWH-G6H67
• Azure Edition does not require a key

How to Download the Windows Server vNext Preview Build 26491

If you’re a registered Insider, you can access the build via the Windows Server Insider Preview download page. Moreover, Microsoft notes that new users can register via the Windows Insiders for Business portal.

via: Deskmodder.de