I have seen a few posts lately in which users ask “What is the Defaultuser0 account?”,”Can it be deleted?” , “What’s its password?, and so on. Officially, Microsoft offers no information about this account and its intended purpose. Or at the very least, any such information is extremely hard to find.
First, let me assure you that Defaultuser0 is an important Windows 10 system account, and that it plays a very important role when installing Windows 10. It exists for one single purpose only: When Windows Setup has finished installing Windows and restarts to OOBE, a user account is required to go through the OOBE until the user creates an initial admin account. OOBE simply couldn’t run without an existing user account.
This is easy to check by yourself next time you perform a clean install. When OOBE starts showing the region selection screen, press SHIFT + F10 to open Command Prompt, and enter command start ms-settings:yourinfo to open current account info in the Settings app. You will see that although you have not created any user accounts, you are running OOBE signed in as Defaultuser0, a local administrator account:
Without this automatically created system account, OOBE couldn’t even start. Of course, there’s the built-in administrator account, but it is disabled by default, and for a good reason. To put it simply, we need Defaultuser0 to get us to point where we will create the first user account for a new Windows installation. Everything is OK, Defaultuser0 belongs to Windows.
When user finally creates the initial user account, Defaultuser0 passes over control to that account, and disables itself. On the desktop with our brand-new, user created account, we can see that although the profile folder for Defaultuser0 is still shown in the Users folder (#1 in screenshot), and Local Users and Groups still lists it as existing account (#2), in fact the Settings > Accounts > Family & Other users clearly shows that this account is disabled, and not added to Windows (#3):
The Defaultuser0 user profile and account has done its job, it will no longer be needed. In fact, DefaultUser0 will be automatically deleted at the next restart. After making the previous screenshot in a fresh, clean Windows 10 install, only seconds after getting to the desktop for the first time, I restarted the computer immediately. After that restart, the Local Users and Groups and Users folder clearly show that the Defaultuser0 account is gone:
Because Defaultuser0 can only be used once, and only to start OOBE, it can never again be used for any purpose, even if it for any reason was not automatically deleted. If it remains in the Users folder as an obsolete profile folder, it can be deleted safely. Defaultuser0 is dead.
So, no panic. Defaultuser0 is just a necessary, temporary Windows 10 system account, born to handle just one task. When that task is done, DefaultUser0 is gone forever.
Author: Kari Finn
A former Windows Insider MVP, Kari started in computing in the mid 80’s writing code for VAX / VMS systems. Since then, he’s worked in a variety of IT positions. He specializes in Windows image capture, customization, repair and deployment as well as Hyper-V virtualization. Kari is a proud Team Member at number #1 Windows site TenForums.com.