
Information
Microsoft has a clear policy to release ISO images for
Windows 10 Insiders only when a build will be released to
Slow Ring. Quite a many of us keen
Fast Ring Windows Insiders create an ISO image from build upgrade UUP files every time Microsoft releases a new build to Fast Ring, to allow test installs on physical and virtual machines, to be used for repair installs and so on. At Ten Forums we have a tutorial to show how to do this, how to use UUP files to create an ISO image:
UUP to ISO - Create Bootable ISO from Windows 10 Build Upgrade Files Installation Upgrade Tutorials
Officially Microsoft does not support clean install scenarios with user made Insider ISO images.
This tutorial will show how to clean install latest Fast Ring Windows Insider build in a fully supported, official way.
Prerequisites:
- Download latest official release of Windows 10, or latest officially released Windows 10 Insider ISO:
- Create USB install media:
Contents
Use links below to go to any part, back button of your browser to return to this list.
Step One
Install Windows 10
1.1) Start installing Windows 10 normally using an officially released ISO image. If you need help in doing so see the tutorial:
Clean Install Windows 10 Installation Upgrade Tutorials
1.2) After a restart or two, Windows setup starts
Windows Welcome, so called
OOBE Mode (Out-of-Box Experience) showing region selection screen:
1.3) Instead of clicking
Yes or changing region settings, press
SHIFT + F10 (press and hold SHIFT key, press F10 key, release both keys) to open
Command Prompt:
1.4) Opening Command Prompt in OOBE activates keyboard shortcuts. You can close Command Prompt immediately, activating
WIN key shortcuts (for instance

+
R to open
RUN prompt) is the only reason we opened it
Step Two
Get Insider build upgrade
2.1) In OOBE, Windows 10 is already fully functional. Because no user accounts have been created yet, Windows setup has created a temporary account
defaultuser0 with local administrator rights to be used until user creates his / her own initial admin account later in OOBE. This temporary user account will be automatically removed when Windows has been fully set up and restarted first time.
We will use this temporary account to get Insider build installed
2.2) Press
WIN + R to open
RUN prompt, type the following and click
OK to open
Settings app:
ms-settings:
Notice that the last character
: (colon) is not a typo!

Note
If you accidentally click outside the Settings app after opening it, it disappears behind OOBE region selection screen. If that happens, press CTRL + TAB to select it in Task View and release both keys to show it again.
2.3) Select
Update & Security, opt in for Insider builds. See tutorial for help:
Start or Stop Receiving Insider Preview Builds in Windows 10

Note
When entering Windows Insider account, be sure to select
Just sign in to this app! Do not click
Next:
2.4) Select
The next version of Windows:
2.5) Select
Fast Ring:
2.6) Let Windows restart and return to OOBE:
2.7) When Windows has restarted, it returns to OOBE mode. Open
Settings app as told in step
2.2
2.8) Select
Update & Security, click
Check for updates:
2.9) Windows Update should find Insider upgrade immediately. Let it be downloaded, initialized and installed:
Notice that depending on your hardware and Internet speed this can take anything from 10 minutes to a couple of hours!
2.10) When done, restart and let Windows install Insider build:
2.11) This process has changed the nature of user account
defaultuser0 (see step 2.1). In normal install it would be a temporary account and be automatically removed after initial user account has been set up. Opting for Insider builds in OOBE using
defaultuser0 we "hijacked" this account making it a local admin account. Windows setup creates a new
defaultuser0 account naming it as
defaultuser0.PCNAME, upgrade process when done will sign you in using this account not asking you to create initial user account as in normal clean install:

Step Three
Finalize Windows setup
3.1) When on desktop, open
Settings, select
Accounts >
Family & Other people and create a user account for yourself, see
Option One in following tutorial if you need help in this:
Add Local Account or Microsoft Account in Windows 10
3.2) The newly created user account is by default a
standard account. It must be made to
administrator account before we continue. See tutorial to learn how:
Change Account Type in Windows 10
3.3) When new admin account has been created, sign out from
defaultuser0 account, sign in to your new admin account
3.4) Checking the
Users folder, you will see that in addition to your user account there's also a profile folder for original
defaultuser0 and, because we "hijacked" it when opting in for Insider builds in step 2.3, a profile folder
defaultuser0.PCNAME. This latter temporary folder will be automatically removed, in fact it might already be removed when you open the Users folder (making screenshots for this tutorial, it disappeared in front of my eyes a second later I had made below screenshot):
Notice that if you check
Settings >
Accounts, only your new admin account will be shown.
3.5) The original
defaultuser0 folder which after normal clean install had been automatically removed must be manually deleted. It does no harm if left there, though:
3.6) Last but not least, take control of
Insider settings in
Settings > Update & Security >
Windows Insider Program:

That's it. You have successfully clean installed Windows 10 Insider Fast Ring build :)
Kari