UAC enables nonadministrator users to perform standard tasks, such as install a printer, configure a VPN or wireless connection, and install updates, while preventing them from performing tasks that require administrative privileges, such as installing applications.

UAC offers the following benefits:

• Most applications can now run without administrative privileges. Applications created for Windows Vista or Windows 7 should be designed to not require administrator credentials. Additionally, UAC virtualizes commonly accessed file and registry locations to provide backward compatibility for applications created for earlier versions of Windows that still require administrator credentials.
  
  For example, if an application attempts to write to a protected portion of the registry that will affect the entire computer, UAC virtualization will redirect the write attempt to a nonprotected area of the user registry that will affect only that single application.


• Applications that require administrative privileges automatically prompt the user for administrator credentials. For example, if a standard user attempts to open the Computer Management console, a User Account Control dialog box appears and prompts for administrator credentials. If the current account has administrator credentials, the dialog box prompts to confirm the action before granting the process administrative privileges.


• Users no longer require administrative privileges for common tasks. Windows Vista and Windows 7 have been improved so that users can make common types of configuration changes without administrator credentials.
  
  For example, in earlier versions of Windows, users needed administrator credentials to change the time zone. In Windows Vista and Windows 7, any user can change the time zone, which is important for users who travel. Changing the system time, which has the potential to be malicious, still requires administrator credentials, however.


• Operating system features display an icon when administrator credentials are required. In earlier versions of Windows, users were often surprised when an aspect of the operating system required more privileges than they had. For example, users might attempt to adjust the date and time, only to see a dialog box informing them that they lack necessary privileges.
  
  In Windows Vista and Windows 7, any user can open the Date And Time properties dialog box. However, users need to click a button to change the time (which requires administrative privileges), and that button has a shield icon indicating that administrative privileges are required. Users will come to recognize this visual cue and not be surprised when they are prompted for credentials.


• If you log on with administrative privileges, Windows Vista and Windows 7 will still run applications using standard user privileges by default. Most users should log on with only standard user credentials. If users do log on with an account that has Administrator privileges, however, UAC will still start all processes with only user privileges. Before a process can gain administrator privileges, the user must confirm the additional rights using a UAC prompt.

• UAC for Standard Users
• UAC for Administrators
• Managing Privilege Elevation
• Application Manifest
• UAC Configuration Options