| mtff | MadgeTech 4 Report Data |
| mtg | Making the Grade Data |
| mth | Derive Math File |
| mtkey | proDAD Heroglyph License Data |
| mtml | Meaningful Text Markup Language Data |
| mtn | PTC Creo Tool Motion Parameter Data |
| mto | FastCAM MTO Data |
| mtp | SpectraMagic NX Template |
| mtst | MotionTracking RAW Image Stack Data |
| mtt | FastCAM MTO Data Template |
| mtt | MetadataTouch Template |
| mttfs | MadgeTech 4 Report Data |
| mtu | Match! User Database |
| mtw | Minitab Worksheet |
| mub | ExtractNow Data |
| muc | Music Collector Collection Data |
| mucow | Adobe Muse Configurable Options Widget |
| mud | Textease Database CT Multi-user Database |
| mudp | Active Safety System Internal Log |
| mulib | Adobe Muse Widget Library |
| mult | SAM Multiple Domain Alignment Output |
| muphlp | MuPAD Help Data |
| murl | Maxthon Browser URL Data |
| musx | Min-U-Script Xpress Data File |
| mut | Integrative Genomics Viewer Mutations List |
| mvf | Autodesk AutoFlix Animation Data |
| mvhlink | MyVirtualHome Link Data |
| mvi | Autodesk AutoCAD AutoFlix Movie Command File |
| mvl | Medison Ultrasound 3D Volume Data |
| mvm | MAGIX PhotoStory Slideshow |
| mvn | Xsens MVN Data |
| mvna | Xsens MVN Subject Dimensions Data |
| mvns | Xsens MVN Session Data |
| mvnx | Xsens MVN Exported XML Data |
| mvr | IBM HotMedia Multimedia Data |