Although this program is not associated with Microsoft, it can be used to open and view MS Project files (xml, mpp, mpt), even though you don’t have the Microsoft software installed on your computer.project viewer extension project viewer extension. The software was developed on Java technology, so in order to run it you need to install first Java Runtime Environment. Download Project 365 Apps to your local PC, MAC, iOS, Android device Project Viewer 365 is the leading viewer for Microsoft Project files allowing users to view, read, share, and print Microsoft® Project MPP files without the need to purchase MS Project Licenses. As you can simply deduct from the software name, this program will open for reading any Microsoft Project files.