If you run a Windows 11 Insider Preview build and have not checked for updates recently, you have less than a week to act. Microsoft’s current flight certificate — the digital signature that validates Insider builds — expires on August 11, 2026. Miss the deadline and your PC will stop receiving new Insider Preview updates entirely.

Windows Insider Program settings page on Windows 11
Image: Microsoft

What is the Windows Insider flight certificate?

Every Windows Insider Preview build is digitally signed with a flight certificate that tells your PC the build is genuine and authorised for testing. Microsoft renews these certificates periodically. The current one was set to expire on August 11, 2026, and Microsoft released updated builds with a fresh certificate on July 27 and July 31 to give Insiders time to update.

This is routine maintenance, not a response to any security issue. Your files, apps, and settings are not at risk — but you do need to install the renewal build before the deadline.

What happens if you miss the August 11 deadline

If your Insider PC is still running an older build signed with the expiring certificate after August 11:

  • Expiration notifications appear — your desktop will show a persistent “This Build of Windows will expire soon” warning on every restart.
  • New builds stop arriving — Windows Update will no longer offer Insider Preview updates to your device.
  • Your PC still works — this does not affect your Windows licence, activation, or day-to-day use. It only blocks future Insider updates.

You can recover after the deadline by manually installing the latest renewal build, but it is simpler to do it now while the update is offered automatically.

Which channels and builds are affected

The deadline applies to all Insider channels except Release Preview. Here are the minimum builds that carry the renewed certificate:

  • Beta (25H2) — Build 26220.9022 (available July 31)
  • Beta (26H1) — Build 28020.2623 (available July 31)
  • Experimental (26H2) — Build 26300.9032 (available July 31)
  • Experimental (26H1) — Build 28120.2630 (available July 31)
  • Experimental (Future Platforms) — Build 29634.1000 (available July 27)

If your build number is at or above these, you already have the renewed certificate and there is nothing more to do.

How to check and update your build

  1. Press Windows + R, type winver, and press Enter. This shows your current build number.
  2. Compare it against the minimum builds listed above for your channel.
  3. If you are below the required build, open Settings > Windows Update and select Check for updates.
  4. Install the offered update and restart your PC — the restart is required for the new certificate to take effect.
  5. If you are unsure which channel you are on, go to Settings > Windows Update > Windows Insider Program to check.

If you have multiple Insider devices, you need to update each one independently before August 11.

Release Preview users are not affected

Devices enrolled in the Release Preview channel do not need to take any action. The certificate renewal applies only to the Beta and Experimental channels, where builds change more frequently and carry separate signing certificates.

For most Insiders, this is a two-minute job — open Windows Update, install whatever is waiting, and restart. The builds released on July 31 also include useful new features like movable taskbar positioning and a smaller taskbar option, so there is good reason to update regardless of the certificate.

Source: Windows Insider Blog