You must set at least the xtd::diagnostics::process_start_info::file_name property before you start the process. The file name is any application or document. In this case, a document is defined to be any file type that has an open or default action associated with it. You can view registered file types and their associated applications for your computer by using the Folder Options dialog box, which is available through the operating system. The Advanced button leads to a dialog box that shows whether there is an open action associated with a specific registered file type.