Files using the MPP extension are Microsoft Project files. Microsoft Project is a productivity application that allows users to create, manage and delegate individual tasks, projects or entire portfolios among user groups. Microsoft Projects files can be saved in any number of Microsoft-supported formats, including the XLS format that is native to Microsoft Excel.
Download and install Microsoft Project if it is not already installed on your machine.
Launch the Microsoft Project application.
Select "Open" from the "File" menu.
Locate the MPP file and click the "Open" button to open the file in Microsoft Project.
Click the "File" menu and select "Save As" from the list.
Click the "Save As Type" pull-down menu and select XLS from the list.
Click the "Save" button to save the MPP file as an XLS document.