Problem: Error show when trying to change the username of a Windows 10 local user account to Administrator. The detailed error message is below.
Windows is already using that name. Please enter a different username.
The username for XXX\XXX could not be changed.
Follow the below solution steps to resolve the “Windows is already using that name” error.
Windows 10 already has a built-in Windows 10 Administrator account which is hidden and disabled for security reasons.
Solution 1: Enable Built-in Windows 10 Administrator account using command prompt
Step 1: Type
cmd in the search field.
Step 2: Right-click the entry for Command Prompt, and select the Run as administrator option.
Step 3: Type
net user administrator. The value for Account active display No.
Step 4: Type
net user administrator /active:yes. The command completed successful message will show.
Step 5: Type
net user administrator. The value for Account active should now display Yes.
Solution 2: Enable Built-in Windows 10 Administrator account using user management tool
Step 1: Open Administrative Tools via the Start menu or Control Panel.
Step 2: Select the Computer Management, and expand the Local Users And Groups. Alternatively, you can type
lusrmgr.msc in the search field to open the Local Users and Groups management console.
Step 3: Expand the Users and double-click the Administrator account.
Step 4: Uncheck the option for Account Is disabled, and click OK or Apply.
Step 5: Close the User Management window.
Step 6: Log out and sign in using the Administrator account.