What is an MDI file?
An .MDI file is primarily a Microsoft Document Imaging File. Microsoft created this format to store scanned documents and printer output as high-resolution images. It functions as a proprietary variant of the standard .TIFF image format. Occasionally, an .MDI file can also be an AIL MIDI driver file used by the Miles Sound System to define MIDI instruments in older video games.
Because the .MDI extension has multiple possible meanings, we recommend using viewer.online/mdi to identify the actual format of your file.
How to open MDI files?
Opening .MDI files on modern computers is challenging because Microsoft removed native support for this format after older versions of Microsoft Office.
Instead of searching for outdated software, viewer.online/mdi can analyze .MDI files to identify the exact format and creator software, inspect the file structure, extract readable text, and check whether an online preview is available.
Software and tools
Historically, users needed Microsoft Office Document Imaging (MODI) to read these files. Today, developers often use imaging libraries that support legacy formats, or specialized document conversion tools. For the audio driver variant, older game engines process the files internally.
Best practices and troubleshooting
If you have an old .MDI document, it is best to convert it into a format that modern devices can read natively. We recommend file conversion to sensible target formats like .PDF or .TIFF on convert.guru.
Summary
viewer.online/mdi is useful for identifying, inspecting, and understanding .MDI files without installing software or dealing with compatibility problems.