Windows 11 is official, but the final version is still weeks away. We’re expecting Microsoft’s new OS to be released in October, although free upgrades from Windows 10 won’t arrive until 2022 for many people.

Until then, your best option is to try out early builds via the Windows Insider Program. These were limited to manual downloads via Settings until August 2021, when Microsoft released the official ISO files. This covers the latest versions available in both the Dev and Beta channels, allowing you to transfer it to a USB drive and cleanly install it on as many PCs as you’d like.

Despite it being officially supported by Microsoft, the process is still quite complicated. Here’s what you need to know.

Check you have enough space

Before proceeding, it’s worth making sure you won’t run out of space at any stage. The Windows 11 ISO file is 5.1GB in size, so you’ll need that spare capacity on the device where it’s being downloaded, any flash drives you’re using and the target devices.

If this is proving tricky, the tips in our guide to freeing up space in Windows 10 could be useful. If there are files you don’t need immediately, it’s worth backing them up and then performing a factory reset. You can then choose what you want back on your PC at a later date.

Download the ISO file

The download process involves signing into a Microsoft account and registering for the Windows Insider Program, if you haven’t already.

  1. Head to the official Windows Insider website
  2. Scroll down to where you see ‘Meet the Windows Insider Program’ and click ‘Register’
    Windows 10 ISO file
  3. You’ll now be prompted to sign into your Microsoft account. If you don’t have one, create it first
  4. From the next page, accept the terms and conditions and click ‘Register’ once more
  5. You’re now officially signed up to the Windows Insider Program. Now, head to the Windows Insider Preview downloads page
  6. Scroll down to the ‘Select edition’ drop-down menu and choose either a Dev Channel or Beta Channel build of Windows 11. The latter is more stable and so recommended for most people
    Windows 11 ISO file
  7. Click ‘Confirm’ and then choose the product language from the next drop-down
    Windows 11 ISO file
  8. Click ‘Confirm’ again, then select ‘64-bit Download’ to begin downloading. The download link is valid for 24 hours from the time of creation
    Windows 11 ISO file
  9. The download will now begin. How quickly it’s completed depends on your internet connection

If you’ve downloaded the ISO file to the only device you want to use it, the process from here is simple. Just double click it in File Explorer and open the Setup.exe. If you need to keep any of your existing files and data, make sure you select this option. Once installed, this will run Windows 11 as if you’ve just got the device out of the box.

However, the process of installing it from a USB is a bit more complicated.

Transfer it to a USB

The first stage is easy. The ISO file will appear in File Explorer (or Finder, if you’re using a Mac), just like any other download. Just plug in your USB stick or other flash drive and transfer it as you normally would – it's a big file, so this may take a minute or two.

Once it’s on the USB, make sure you eject it before unplugging.

Run Windows 11 from the USB

This is where things get tricky. That USB stick you’ve just used needs to be made bootable for it to run Windows 11 once it’s plugged in. Microsoft recommends using Rufus for this:

  1. Download and run the latest version of Rufus (3.15 at the time of writing) to the device where Windows 11 has also been downloaded
  2. Insert the USB which the ISO file will be mounted on. Make sure it has at least 8GB free and all other files have been removed
  3. From the main Rufus window, choose the relevant USB under ‘Device’
  4. Select ‘NTFS’ under ‘File system’ and ‘MBR’ under ‘Partition scheme’
  5. To the right of ‘Boot selection’, click ‘SELECT’ and choose the ISO file
  6. Click ‘Start’ to begin the process – how long this takes depends on the speed of your USB stick
Rufus
Image: Rufus

Once complete, you now have a USB stick that can be used for a clean installation of Windows 11 on any compatible device.

  1. Plug the USB stick into the target device
  2. Restart the device
  3. Before the Windows logo appears, hold the F8 key to enter Safe Mode
  4. From here, choose ‘Use a device’ and select the USB stick

Your PC should now boot running the Windows 11 ISO file you downloaded. If not, you may need to turn off Secure Boot in the BIOS settings.

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