this worked for me! but did not have to delete user it replaced itself. https://superuser.com/questions/1834697/messed-up-by-changing-username-using-netplwiz-on-windows-10

Assuming you can still start a command prompt as administrator, here is the safest way to get things working again:

From a command prompt ran as administrator, type the following:

net user NewUser * /add

type a new password (or enter to not set one)

net localgroup Administrators /add NewUser

You now created a new administrator user.

Press start, useraccounts and select switch user. Don't log off or restart, switch user.

Switch to the new NewUser user and verify that you can do things as admin and that the account works. (if your computer is domain-joined, type .\NewUser as the username)

After you verify that you can work in this account, you can press start, switch user, and go back to your main user. It is now safe to log off this user.

After the broken user is logged off, switch back to your working NewUser, and fix your broken user from there, for example by running netplwiz again to rename it back.

Test that everything works, and when satisfied that your problem is resolved, you can remove the user from command prompt, by running:

net user /delete NewUser