How did account "defaultuser0" get created? Why?

I notice that there's an account called "defaultuser0" on my Win 10 computer.
It's not available at the login screen.
It does not show up in the User Accounts control panel.
But it does show up in file/folder permissions. For example, running command line "icacls" on the Desktop folder gives this:

Code:

Desktop BUILTIN\Administrators:(OI)(CI)(F)
        NT AUTHORITY\INTERACTIVE:(OI)(CI)(RX)
        NT AUTHORITY\SYSTEM:(OI)(CI)(F)
        BRUCEDELL\defaultuser0:(OI)(CI)(D,DC)
        BRUCEDELL\userA:(OI)(CI)(F)
        BRUCEDELL\userB:(OI)(CI)(F)
        BRUCEDELL\userA:(OI)(CI)(IO)(DE,DC)

What's up with this rogue/phantom account?

You can also delete the user with net user defaultuser0 /delete and delete from HKLM\Software\Microsoft\Windows NT\CurrentVersion\ProfileList\

There is a long thread (more than a year) about this bug in the link below and it seems it isn't resolved yet. I certainly still get it on clean install - no particular pattern except some machines do it more often than others.

created on clean install of Anniversary Update - Microsoft Community

It doesn't really matter as you can't use defaultuser0 credentials anyway but it is certainly sloppy.

Kari said:

I repeat: defaultuser0 is, although temporary, an important system account. It is absolutely not a bug nor created because of a bug.

The bug is it isn't always deleted. If it is temporary profile it should be deleted (not only from C:\Users but from net user, registry etc) after your clean install completes. If it was meant to remain it would always remain but clearly this isn't the case.

No-one know why it isn't always deleted although there is much speculation.

I've deleted the defaultuser0 account, following instructions found here and elsewhere.

Thanks for the help.

margrave55 said:

I've deleted the defaultuser0 account, following instructions found here and elsewhere.

Thanks for the help.

Out of interest, what did you do?

I delete C:\Users\defaultuser0 directory and run net user defaultuser0 /delete

I'm not sure whether deleting all the other stuff is required.

It would be certainly interesting if MS came up with an answer but apart from a vague commitment to it being fixed in April 2017 release (it was not) we heard nothing.

I imaged a classroom of 30 computers with the same image. Two of the computers had the defaultuser0 come up on the sign in screen. The others did not. Deleting the user did not work. The only thing that did was imaging them again.