Download Windows 11 ISO: Build 26300.8493, 29591, and 28020.1863 (Insider Preview)

• The official Windows 11 ISO files for builds 29591, 26300.8493, 26220.8474, and 28020.1863 are available through the Insider Preview Downloads page.
• The ISOs are available for the Experimental and Beta channels, allowing users to perform a clean install or an in-place upgrade to test upcoming features and improvements.
• These preview versions aren’t final and should be used on secondary devices.

Microsoft has updated the availability of official ISO images for the latest Windows 11 Insider builds, making it easier to test upcoming features with a clean setup or an upgrade path.

The company is now offering ISO downloads for builds 29591.1000, 28020.1863, 26300.8474, 26220.8493, 28000.1896, and 26200.8328 through the Windows Insider Program preview downloads page. These images cover the Experimental and Beta channels, giving early adopters and developers access to the newest platform changes before they roll out broadly.

These ISO files are particularly useful if you want to perform a clean installation, set up a virtual machine, or carry out an in-place upgrade without waiting for the update to arrive through standard channels. It’s the fastest way to explore new features and system improvements included in upcoming versions of Windows 11.

However, it’s important to remember that these are preview builds. They are not finalized releases and may include bugs, incomplete features, or stability issues. For that reason, installation is best limited to secondary devices or controlled environments such as virtual machines.

If your device is already enrolled in the Windows Insider Program, there’s no need to download the ISO manually. You can receive the same builds directly through Windows Update by checking for updates in system settings, which remains the simplest way to stay up to date with the latest Insider flights.

Windows 11 build 29591 ISO file download

Microsoft currently offers several versions of the Windows 11 ISO for download through the Insider program. You can select the build that matches your testing requirements from the “Select edition” drop-down menu:

Experimental (Future Platforms & 26H1)

These builds are for those who want to see the earliest features, though they can be less stable.

• Build 29591.1000 (Future Platforms): Available in standard, Enterprise, and Home China SKUs.
• Build 28020.1863 (26H1): Available in standard, Enterprise, and Home China SKUs.
• Build 26300.8474 (25H2): Available in standard, Enterprise, and Home China SKUs.

Beta Channel (25H2)

The Beta channel is ideal for users who want to try upcoming features that are closer to being finalized.

• Build 26220.8493 (25H2): Available in standard, Enterprise, and Home China SKUs.

Release Preview Channel (26H1 & 25H2)

This is the most stable Insider branch, typically used to test builds just before they roll out to the general public.

• Build 28000.1896 (26H1): Available in standard, Enterprise, and Home China SKUs.
• Build 26200.8328 (25H2): Available in standard, Enterprise, and Home China SKUs.

After downloading the official ISO file, use tools like Rufus to create a USB flash drive to install the operating system. Alternatively, you can mount the ISO to begin the setup if you plan an in-place upgrade.

If you are looking for the latest build or any other build, you can create a custom ISO file using the UUP tool.

Microsoft frequently updates these ISOs. For a complete list of every version released to date, including those no longer in the ‘Select edition’ menu, check my Windows 11 Build Tracker.

Update May 13, 2026: This page has been updated to ensure accuracy and include the latest information.