How to Open an MDI File

MDI, short for Microsoft Document Imaging, is a proprietary Microsoft file format. MDI files can be viewed in OneNote or MDI Viewer; both are included in versions of Microsoft Office prior to Office 2010. OneNote is installed by default with the other Office programs, but the MDI Viewer app must be activated before it can be used to view an MDI file. MDI files contain images that are similar in quality to a TIFF but require less space on a hard drive.

Click on the "Start" menu and select "Control Panel."

Click "Programs" and choose "Uninstall a Program."

Scroll to Microsoft Office (you must have either Office 2003, 2007 or XP installed). Click "Change."

Select "Add or Remove Features," and then click "Continue."

Open the "Office Tools" menu, then open the "Microsoft Office Document Imaging" drop-down menu.

Select "Run All From My Computer." Choose "Continue" and "Close" to complete installation.

Restart your computer.

Double-click on the MDI file to open it.