A user account varies depending on what the user is storing in their account. A little used account can be 50KB while an account with a lot of music or videos could be 200GB or more.
Depending on how you mean it, it's either some one who "uses" a Mac or a Mac that has a "User" account. When you first log into a Mac you make a "User" account so it can be separated from other people that use it, keeps them from accessing your stuff. Jane and Bob both use one Mac so Jane and Bob have there own accounts, Jane has a separate user account so Bob can't mess with Janes settings or access her other stuff.
The "Guest" account, when created by an administrator, does not have a password. If the administrator created a "User Account" called 'Guest' then the administrator may have given it a password. If you are an administrator of the Mac and you are having trouble with the guest account, delete it and restart. Then create a new 'Guest' account by selecting "Guest" in the control panel. The Guest account creates a temporary work area for a guest on the Mac, and deletes all the files created by the user when the Mac is shut down, or the user logs off.
User accounts can be set up in the Accounts section of System preferences.
The Registered User is the account (name/password) you use on the PC. Connecting as a Guest will not require the name/password but may limit what you can access on the PC from the Mac.
Mac OS X stores a user's System Preferences settings in the Preferences folder within the Library folder in the user's account.
iChat uses the AIM network so a Windows user with an AIM account (See links below) will be able to contact a Mac user with iChat.
A Local user account is a user account that is part of the domain or work group.
Mac GUI
"Having your own account with a picture as a background" Jhonn Green "each person has there own user account" mac osx install "A picture??" ME!
If it only logs into one account when it restarts then have them log out and not restart and then you should have a list of other user accounts.You can set it up to list the user accounts when you restart or turn it on or off to solve that problem.
Mac OS X stores fonts in both the Font folder in the Library folder at the top hard disc level and also in a individual user's account Library Font folder.
It is called User Account Control.