How to ..
The first time you started your Mac you would have created a User Account and registered the computer. Usually it will be in your name or another name you have chosen, but you can have User Accounts for all the other people who will use the computer, kids, partners or friends. It is a good idea to set the computer up this way so everyone who uses it keeps their files, pictures, emails and music separate.
Each User Account has it's own settings so each User can have their own choice of Desktop picture and Screensaver, their own Dock layout.
Look in System Preferences and find Users & Groups on the lower left side, click it to open:
The initial account that was set up was an Administrator Account. Each computer must have at least one Administrator account because only administrators can install software and create other User Accounts.
The other accounts that you create can be Standard accounts which can't create other users or install software and can be managed; for example you can use Parental Controls to limit the amount of time a child can use the computer and control what website they can view. (See Parental Controls. Or they can be Administrator accounts.
First you will need to unlock the padlock icon at the bottom left of the window so you can make the changes, it will require the password you entered when you made your first account.
Click the + icon at the bottom of the screen and a window will apear asking what name you want to give the account, what password you are going to use and with a pop up menu to choose what type of account.
You can Tab between the diferent fields and the computer will make the Account Name from your Full Name field unless you choose to enter something else. You don't need to enter a password! If you leave the password field blank then the computer will ask if you are sure you don't want a password when you click the Create Account button!
Many people don't have a password on their computer — its just one less thing to forget! Obviously it means that anyone can access your User Account so it's a decision you need to make depending on your circumstances. In our modern security concious world a password is a good idea — just don't forget it...
OK, so you have made a new User Account for someone else to use your machine. What about deleting an existing Account?
Very simple: select the account you want to delete and click the - button and the computer will ask if you want to save the contents of the User Account or just delete it. Choices, choices! Usually you will Delete it immediately.
* You cannot delete the account that is active, that you are logged into. That will be at the top of the list. you need to log out of the Account you want to delete if already logged into it and log in to an Administrator Account first.
* Only an Administrator Account can delete another account.
* You can't use the same name as an existing Account.
To Log Out of an Account go to the Apple menu top left of the screen and choose Log Out:
The computer will take you to the Login Window which has a list of the User Accounts that are on the computer so you can choose which one you want, enter the password when prompted and off you go. If there is no password just click OK.
If You Sell Your Computer and set up a new account for the new owner it's also a good idea to change the computer name which is usually set as your name. Look in System Preferences then Sharing:
Change the Computer Name: field to anything you like, usually the new owner's name.
Fast User Switching: This is a cool way to switch between acccounts so that all the applications that are open stay open. Logging out quits everything, Fast User Switching keeps it active.
First you need to turn it on by going to the main Accounts page and clicking Login Options to bring up this window:
At the bottom of the page is the box to tick, not surprisingly called Show fast user switching menu as:
Leave it as Name and on the top left of your computer screen will appear your Account name and if you click that you will see all the other Accounts on the computer. Switching is as simple as clicking the one you want to switch to, entering the password if there is one and watching the rather cool Cube effect as it switches.
The only thing to be aware of is that when you have Fast User Switching turned on if you want to Shut Down or Restart the computer you will be asked for an Administrator Account Name and Password...