There are a couple of places on your Mac where your name, or some other name, might appear: the account name and the Home folder. The name that appears is based on the Full Name you provided when you (or your administrator) first set up the account.
But what if you want to change your username as it appears in these locations? You may have already been married and now have a new name (or you just got divorced). Maybe IT misspelled your name when they set up your Mac. Maybe your first and last name spell something offensive, or it might be time to change what was once a fun username to something more formal. Maybe your current short name isn’t really short and it’s a hassle to type it every time you’re asked for your username. Maybe you have two or more Macs and want to use the same short username on all of them. Or maybe you inherited a Mac and would rather just rename the existing account than create a new one.
Fortunately, since Mac OS X Leopard was released in 2007, Apple has made it reasonably easy to change the short username and startup folder name from System Preferences. Before Leopard, changing your short username was a complicated and risky procedure.
However, there are still some limitations:
The short name and the home folder name must match, so if you were hoping to give your home directory a comedy name, but wanted the short name to be something more formal, you were out of luck.
Despite what we said about it being a less risky procedure, it is the type of change that could lead to data loss if you do something wrong. So make sure to make a backup first!
You cannot change the name of an account while you are logged in to the account you are changing. Therefore, you will also need to be logged into a different (administrator) account to do this; you may need to create it first.
If you need to create a new administrator account, follow these steps:
Open System Preferences > Users & Groups.
Click on the lock icon and enter your password.
Click on the + sign.
Change New Account to Administrator.
Give the account a name and password.
Click Create User.
If you have forgotten your password, please read: How to Recover a Forgotten Mac Password.
Alternatively, you can make an existing account an administrator.
Open the Users and groups preferences pane.
Click the lock icon in the lower left corner and authenticate.
Select the account in the list on the left.
Check the “Allow user to manage this computer” box.
macOS notes that you must restart your Mac for it to take effect; just do it
How to Change Mac Username
Now that you’ve set up this alternate admin account, it’s easy to change your account username. But you will see a pretty clear warning that changing the settings could harm the account and prevent you from logging in, so be careful!
The first thing you need to do is log out of your account and access this new administrator account:
Click the Apple logo and select Sign Out [your name]
Then enter the new administrator account name and password.
Now you are all set to change the username of your regular account. Follow these steps to change the username:
Open System Preferences.
Click Users and Groups.
Click unlock and enter your password (for the admin account you are using).
Now Control-click or right-click on the user you want to rename.
Choose Advanced Options.
Change the name in the full name field.
Reboot the computer for the changes to take effect.
This will only change the username, not the home directory name or its short name. And, as the warning says, it can damage the account and prevent you from logging in!
We made it through without any issues, although there were a few creepy seconds where the login process took a bit longer than usual.
How to change the name of the home folder and the name of the account
Renaming your home folder (and your account name, which is linked and, as you can see in the image above, grayed out) is more involved.
As before, you must log out of the account in order to change it. So if you’re not already on the separate admin account, log in to that.
Here’s how to change the home folder name and account name:
Go to the Users folder on your startup drive (to find it, open Finder and click Go > Computer)
This should open the Macintosh HD [or Untitled/whatever name your computer has] file.
Inside the Macintosh HD folder is the Users folder; click to open it.
Inside the Users folder, you’ll find the home directory of the account you’re renaming. (Write this down, as you will need it later.)
Click on the folder and rename it. (Note the old and new name because you’ll need it once again.)
Enter the password for the administrator account you are using when prompted.
How to change your username
After you have renamed your home folder, you now need to change your username; if you don’t, there will be problems because they both need the same name. You must also change the name in the field that shows the location of the home directory.
Open System Preferences > Users & Groups.
Click unlock and enter the password of the administrator account you just logged in with.
In the list of users, Control-click or right-click the user whose name you want to change.
Select Advanced Options.
Change the Account Name field to the new name you just assigned to the Home folder for that user.
Next, change the home directory field to match the new name you gave the home folder.
Close System Preferences.
Restart the Mac.
Sign in to the renamed account
If you have any trouble logging in, check that the account and directory names are the same.
Need to change your admin password? Here’s how to change the administrator password on a Mac.
You may also want to make signing in to your Mac even easier. Did you know that if you have an Apple Watch, you can use it to sign in automatically? Here’s how to unlock and sign in to your Mac with an Apple Watch.