Solution

When you use the User Accounts control panel applet, you can't actually change the logon user name but just the full, display name. This way the name can be changed at any time without side effects (e.g. classic user logon).

1. Log off, and log on with an administrator account.

2. Press Win+R, type or paste netplwiz.exe in the text box, and press Enter.

3. Select the account you want to rename from the list, and click Properties.

4. Rename it as you like, and click OK when done.

Remarks

• If you're using Professional or higher editions you can achieve the same result by running lusrmgr.msc.

• Logon user names are limited to 20 characters for backward compatibility. Unlike full names, they can't contain dots, spaces, or any of the following characters:

  \ / " [ ] : |  + = ; , ? * @
  

• Changing a user name won't have any effect on the associated Security Identifier (SID), which is generated when the account is first created. Under the hood, Windows uses SIDs to handle accounts regardless of their names. This means you don't need to change the privileges or permissions on the renamed account.