How to Change the Admin Username and Password on my MacBook.

Sometimes there might be a problem that when you forgot your admin username and password OR , when you install any software or perform any activity that requires the admin password and on being providing the correct username and password , it doesn't forward or  detect.
It's because of you may be a Standard User.
In order to change the User from Standard to Administrative , you have to create a new User which must be admin type so that you  have all the system level permission.

You might have also used all the standard traditional methods to reset your password, yet failed. You’re now desperately looking for a final resort to getting access back to your account.
Don't worry here I will show you how to create a new Admin User using Single-User Mode.
This method should allow you to reset an OS X account and restore access to your account via the use of Terminal Single User mode, which is a bit tricky, but extremely helpful.

First of all , power off your Mac and then hold command + S and boot up your Mac. This will open a Terminal in Single-User mode on your Mac .
You’ll know that Terminal has successfully opened when you see white text appear on your Mac’s screen :

Now, enter the following commands into Terminal, one at a time. Press Enter after each command :

(1).   /sbin/mount -uw /

(2).   rm /var/db/.applesetupdone

(3).   reboot

This is what the above commands will do:

1. Mount the internal hard drive with write permission
2. Remove the Mac setup file. This is the file that OS X checks to determine if the system is already set up.
3. Restart the Mac .

Your Mac will be restarted and you’ll be presented with the Mac Startup Setup screen, as shown below :

Once you’re logged in to this new account, open up System Preferences, either from Spotlight or by navigating to “Applications -> System Preferences”.

 In System Preferences, click on “Users & Groups.” Once that opens, click on the Lock icon in the bottom-left corner to authenticate yourself.

Once you’re authenticated as a system admin, select the account whose password you want to reset from the left-hand pane. Click on “Reset Password” to change the password for the account, and hence, regain control.

Now log out, log back in to your original account, and continue with your work.

Let us know in the Comments section below whether the above method worked for you. If not, how did you regain access to your OS X account?

THANKS.