Use the Required Execution Level setting to specify the minimum level required by your installation's Setup.exe file for running the installation (the setup launcher, any setup prerequisites, and the .msi file) on Windows Vista platforms. The available options are:

- Administrator—Setup.exe requires administrative privileges to run. Administrators must authorize it; non-administrators must authenticate as an administrator.
- Highest available—Setup.exe prefers administrative privileges. Administrators must authorize it; non-administrators run it without administrative privileges. This is the default option for InstallScript and InstallScript MSI projects.
- Invoker—Setup.exe does not require administrative privileges, and all users can run it without administrative privileges. Setup.exe does not display any UAC messages prompting for credentials or for consent. This is the default option for Basic MSI projects.

For InstallScript and InstallScript MSI projects, and for Basic MSI projects if the Setup Launcher setting is set to Yes, InstallShield embeds a Windows Vista application manifest in the Setup.exe launcher. This manifest specifies the selected execution level. Operating systems earlier than Windows Vista ignore the required execution level.

If the Setup Launcher setting is set to No for a Basic MSI project, InstallShield does not embed the Windows Vista application manifest in the Setup.exe launcher.

The benefit of elevating the required execution level is that privileges can be elevated only once if necessary to run Setup.exe, and that these privileges can be carried over to all of the installation's prerequisites and the .msi file without requiring multiple prompts for approval. Thus, if two of your prerequisites require administrative privileges, for example, you can change this setting to Administrator, and then end users are prompted only once during the installation, before Windows Installer runs the Setup.exe file. Note, however, that if you elevate the privileges and also launch the application at the end of the installation, the elevated privileges are carried over to the application. In most cases, running an application with elevated privileges on Windows Vista platforms is discouraged.

Note that an end user's installation experience is more secure when installations are run with only the permissions that they need. Unless an application is designed to be run only by system administrators, it should be run with the least privilege.