| mgrp | NI Maschine Group File |
| mgspot | MacGourmet Spotlight MetaData |
| mgtheme | MacGourmet Theme |
| mgw | Microgateway Policy Implementation Data |
| mgz | Compressed MGH MRI Data |
| mhd | ITK MetaImage Header |
| mhe | Hackshield Heuristic Engine File |
| mhl | Media Hash List |
| mhm | Microsoft Mouse and Keyboard Center Macro |
| mhp | Maths Helper Plus Data |
| mhs | Xilinx Microprocessor Hardware Specification |
| mi2 | AutoDesk Softimage Data |
| miaf | InstallAware Setup Dialog Rules |
| mib | SNMP MIB File |
| mif | mAirList Inline File |
| mif | Xilinx CORE Generator Memory Initialization File |
| mif | Elmer Mesh Generator Input File |
| miigx | SaveGame Manager GX Mii Data |
| mim | MIME Encoded Data |
| mime | MIME Encoded Data |
| mindnode | MindNode Document |
| miniml | MINiML File |
| mir | Mail.dat Manifest Individual File |
| mit | MineEdit Inventory Template |
| miv | MapImagery Vendor Profile |
| mix | VentaFax Voice Message Batch |
| mi_ | Compressed MID File |
| mj | MovieJack DVD Ripper File |
| mj | Palladio ModelJoin Query File |
| mjd | Mime-encoded JDF |
| mjk | Adobe Illustrator Mojikumi Set |
| mjm | JMF Mime Package |
| mjs | Mijas 7400 Costing Database |
| mjx | Objectif Lune Sugopita Data |
| mk4 | Schiller Medilog ECG Raw Data File |
