i also like to know that!! To quote Microsoft: "Orca.exe is a database table editor for creating and editing Windows Installer packages and merge modules. The tool provides a graphical interface for validation, highlighting the particular entries where validation errors or warnings occur." It's part of the Platform SDK Components for Windows Installer Developers. It is available as a web download here: SDK x86 Web Install Other Versions are available here: Platform SDK Or a full ISO download: SDK ISO Download