Deeper look at running Windows Insider Preview Builds

What are Windows Insider Preview Builds?

Windows Insider Preview Builds are early versions of Windows that are not yet released to the public. By running Insider Preview builds on your device, you can preview what we're working on next, give us feedback, and help shape the future of Windows. Once you've registered for the program, you can run Insider Preview builds on as many devices as you want, each in the channel of your choice.

A visible watermark shown at the lower-right corner of the desktop is normal for these pre-release builds.

What are channels?

We release Insider Preview builds through channels. Each channel is designed to provide a different experience based on how early you want to preview features in Windows, which affects how early your voice impacts the development of Windows. When choosing a channel, keep these things in mind:

1. How early in development you'd like to see features and changes.
2. How stable you need your device to be.
3. The types of issues you're willing to encounter on your device.
4. Whether or not you need Microsoft support.

Check out Flight Hub for a complete look at which builds are available in each Insider channel.

Experimental channel

The Experimental channel is usually where new features and ideas are released first and is ideal for tech enthusiasts. Insiders in the Experimental channel can access the latest Windows 11 preview builds as we incubate ideas and develop features with longer lead times. You should expect some rough edges and variable stability in this channel.

Features and experiences included in these builds might never get released as we try out different concepts and gather feedback. Features might change over time, be removed, or be replaced and never get released beyond Windows Insiders. Some of these features and experiences could show up in future Windows releases when they're ready.

Many features in the Experimental channel are rolled out using Controlled Feature Rollout (CFR) technology, starting with a subset of Insiders and ramping up over time as we monitor quality feedback before pushing them out to everyone in the channel. If a feature has been announced and you don't see it on your device, go to the Feature flags settings page to see whether you can toggle it on manually. For more information, see Feature flags.

Some preview features in active development with Windows Insiders might not be fully localized. Localization improves over time as features are finalized. If you see localization issues, report them through Feedback Hub.

Beta channel

The Beta channel is for early adopters and IT professionals who want to see what we plan to ship in the coming weeks and validate the latest Windows updates and features, but still need reliable updates.

As part of the Beta channel, you'll receive builds tied to a specific upcoming release, such as one of our H1 or H2 servicing releases. Your feedback is especially important here because it helps engineers ensure key issues are addressed before the next release milestone.

Feature rollout in the Beta channel doesn't use Controlled Feature Rollout technology, which means all users get the same features and experiences. You might occasionally see small differences within a feature as we test variations, but the feature itself will always be on your device.

Although the Beta channel represents features closer to general availability and a higher level of polish, this is still prerelease software. Features and experiences included in these builds might never get released, might change over time, be removed, or be replaced and never get released beyond Windows Insiders.

As with the Experimental channel, some preview features in active development with Windows Insiders might not be fully localized. Localization improves over time as features are finalized. If you see localization issues, report them through Feedback Hub.

Although new features usually land in the Experimental channel before Beta, the two channels represent parallel engineering paths, so there might be cases where features and experiences appear in both channels at the same time.

Release Preview

In Release Preview, Insiders and IT professionals get the upcoming version of Windows before it's released broadly, with advanced quality updates and certain key features. These builds are also supported by Microsoft if you're in the Windows Insider Program for Business.

To select Release Preview, enable it in Advanced options, but the content remains unchanged.

Understanding Windows core versions

Windows ships on different core versions, which represent how we develop the OS and keep it up to date. We added the capability for advanced users to pick a Windows core version within the Experimental and Beta channels under the Advanced options tab when first enrolling in the Windows Insider Program. While we generally suggest staying on the build recommended for your device (which is selected automatically if you don't select Advanced options), there might be cases where you want a specific Windows core version.

Most users will see options such as Windows 11, version 25H2/26H2 and Windows 11, version 26H1 builds, which align to their respective retail builds. Both builds are active development branches of Windows, with version 26H1 being a targeted release to support specific silicon in the Windows hardware ecosystem. See here for more information on Windows 11, version 26H1. Because these represent different Windows development cores, if you choose to install version 26H1, you can't go back to the 25H2/26H2 build without doing a clean reinstall of Windows. This is because version 26H1 represents a higher version development core than 25H2/26H2.

Accordingly, users entering the Windows Insider Program on devices that shipped with Windows 11, version 26H1 in retail won't be able to select version 25H2/26H2 as an option when selecting Advanced options.

The Experimental channel also contains an additional build version called Future Platforms, available to all users, and it is our earliest preview build of Windows. This build core version is aimed at highly technical users who want to preview platform changes that require a longer lead time before release. Examples include major changes to the Windows kernel and new APIs.

The builds released to Future Platforms represent platform changes early in the development cycle and should not be seen as connected to any specific retail release of Windows. Because of this platform-change focus, Insiders who want to try the latest features should choose the default option for their channel, or a Windows core version aligned to a retail build.

Because Experimental (Future Platforms) doesn't align to a retail build, removing a device from the program requires a clean install of Windows 11. Insiders are also unable to directly switch to a different channel without doing a clean installation of Windows 11 due to technical setup requirements.

Switching between channels

In most cases, you can move between the Experimental channel, Beta channel, and Release Preview on the same Windows core version without doing a full device OS wipe. This is enabled by using an in-place upgrade (IPU) to hop between versions. An IPU takes more time than a normal update but migrates your apps, settings, and data in place.

You can change channel by updating your channel selection in Windows Insider Program settings.

Because Experimental (Future Platforms) is our earliest preview build option and doesn't align to a retail production build of Windows, moving to a different channel or leaving WIP still requires a clean install.

Switching channels

Applies within the same Windows core version:

• Release Preview to Beta channel or Experimental channel.
• Beta channel to Experimental channel or Release Preview.
• Experimental channel (excluding Future Platforms) to Beta channel or Release Preview.

1. Go to Settings > Windows Update > Windows Insider Program.
2. Select Choose your Insider settings.
3. Choose the radio button beside the channel you'd like to switch to. Your settings update to your new channel.
4. The next time you receive an update, it will be for your new channel.

Moving out of Experimental (Future Platforms)

If you're in Experimental (Future Platforms) and want to move to a different channel or Windows core version build, you need to:

1. Do a clean installation of Windows on your device with these instructions.
2. Once you've reinstalled Windows, go to Settings > Windows Update > Windows Insider Program to set up your device again, making sure you select the channel you'd like to move to. Learn more about setting up your device.

Feature flags

Feature flags are available for Insiders in the Experimental channel that lets you manually turn specific features on and off, even if CFR is being used to gradually roll out that feature. Feature flags can be found under Settings > Windows Update > Windows Insider Program > Feature flags.

Screenshot of the Feature Flags page in Settings.

We start by enabling Feature flags for visible new features announced in WIP. This means less visible changes announced in WIP, such as bug fixes and system improvements, might not be present in Feature flags.

Understanding updates

After you've set up your device and installed your first Insider Preview build, you'll start getting updates based on the channel experience you picked. With each new update, you'll see a new build number, and that number can help you understand what you'll see in the build.