Windows Insider Preview Activation
You will need to install the Windows Insider Preview build on a device that has been previously activated with Windows or with a Windows product key, or after a clean install, attach a Microsoft Account (MSA) that has a Windows license digital entitlement linked to it.

Windows Insider Preview Activation
You will need to install the Windows Insider Preview build on a device that has been previously activated with Windows or with a Windows product key, or after a clean install, attach a Microsoft Account (MSA) that has a Windows license digital entitlement linked to it. For more details please see the article: Activation in Windows.

Remember, trying out an early build like this can be risky. That's why we recommend that you don't install the preview on your primary home or business PC. Unexpected PC crashes could damage or even delete your files, so you should back up everything.
If you want to stop using Windows Insider Preview and return to your previous version of Windows, you'll need to reinstall your previous version from the recovery or installation media that came with your PC-typically a DVD. If you don't have recovery media, you might be able to create recovery media from a recovery partition on your PC using software provided by your PC manufacturer. You'll need to do this before you upgrade. Check the support section of your PC manufacturer's website for more info.
If you use the ISO to do a clean install of the Windows Insider Preview, you won't be able to use the recovery partition on your PC to go back to your previous version of Windows.
After you install this new build from the ISO, it's important to verify your Windows Insider Preview settings are correct to continue receiving additional preview builds from your selected flight ring.