.mpp file are file extension for Microsoft Project file. By default, we need to have Microsoft Project to open the .mpp file.
It is possible to open a .mpp file without having MS project. There are 2 option we can do that.
1st option – using web browser project viewer.
- Click Here to access free online Microsoft Project Viewer
- For your information, this free online Microsoft Project Viewer only support .mpp files size up to 400KB.
- Here is the screen shoot

2nd option – Install Open Source Project Alternatives
a) GanttProject
GanntProject is a project scheduling and management tool which same as Microsoft Project. GanttProject able to import and export Microsoft Project files (.mpp). It runs on Windows, Linux and Mac OS X.
Click Here to download GanntProject
How to open .mpp file with GanntProject
- After you install GanntProject, launch the GanntProject application
- Click on Project -> Import from the menu bar

- Select Importer. Select Microsoft Project files from the pop up screen and click Next
- Select the Microsoft Project files that you want to import and Click OK to import the Ms Project Files



- Now your Microsoft Project files has been imported to GanttProject.

b) OpenProj
OpenProj is another free, open source desktop alternative to Microsoft Project. It’s available on Linux, Unix, Mac or Windows.
Click Here to download OpenProj. Install the project. After install, just double click the Microsoft Project files. Microsoft project files will automatically import to OpenProj

You could also use LiveProject, which is available in a free version. It allows you to see your project files, including dashboards, printing and exporting, and just lots of features. It would be great if you could add it to your list, I think your readers might find it interesting.
Full disclosure: I’m the founder of KaDonk which makes LiveProject.
using project management software, such as Steelray Software, can make using Microsoft Project much easier.
Thank you for sharing. I will try it.
http://www.amiproject.com
http://www.amiproject.com is another free web-based MPP files viewer
There is one information about OpenProj.
According to our experience, after you installed it(Version 1.4) op your computer,it is possible happening trouble on your Microsoft Office Suite:
1. Word, PowerPoint display “Clip Art” or pictures abnormal;
2. Some word document cannot save;
3. Some PowerPoint document cannot save;
The solution are:
1. Move your account name into local administrator group;
2. Delete current user profile folder
(C:\Documents and Settings\Your Account Name)and create new one;
MOOS Project Viewer is a free Microsoft Project viewer that is running on Windows, Mac OS X and Linux
You can also try MOOS Project Viewer, which works on Windows, Mac OS X and Linux.
Thank you for your recommendation
Thank u for sharing