The Windows Installer engine (also called the MSI engine) drives the installation of your application. It is a part of the Windows Installer Service, a technology developed by Microsoft to standardize installations on the Windows platform. Without the Windows Installer engine, installations using the Windows Installer technology cannot be installed. The Windows Installer engine is already installed on Windows XP. For other operating systems, the Windows Installer engine must be installed by the installation or by the home user. Most installations based on the Windows Installer Service automatically install the Windows Installer engine on the computer prior to running the installation. In case of an error or other unexpected behavior, you may need to install the engine manually. For more information, see How Do I Install the Windows Installer Engine on My Computer?