| mu | Quattro Pro for DOS Menu Data |
| mub | ExtractNow Data |
| muc | Music Collector Collection Data |
| mucow | Adobe Muse Configurable Options Widget |
| mud | Act! MUD Data |
| mud | Textease Database CT Multi-user Database |
| mudp | Active Safety System Internal Log |
| mui | Amiga MUI Default Class Data |
| mulib | Adobe Muse Widget Library |
| mult | SAM Multiple Domain Alignment Output |
| mum | MATLAB Unit Operation Model |
| muphlp | MuPAD Help Data |
| murl | Maxthon Browser URL Data |
| musc | eXtendable Wad Editor MUSC Data |
| musicdb | Apple Music Library |
| musiclibrary | Apple Music Library |
| musx | Min-U-Script Xpress Data File |
| mut | Integrative Genomics Viewer Mutations List |
| mv85 | Adobe Director for Mac Video |
| mv93 | Adobe Director for Mac Video |
| mv95 | Adobe Director for Mac Video |
| mvd | MACE Velocity Data |
| mvd | MicroVision Database |
| mvd2 | Volocity 3D Data Set |
| mvf | Autodesk AutoFlix Animation Data |
| mvg | ImageMagick Vector Graphics Data |
| mvhlink | MyVirtualHome Link Data |
| mvi | Autodesk AutoCAD AutoFlix Movie Command File |
| mvl | Medison Ultrasound 3D Volume Data |
| mvm | MAGIX PhotoStory Slideshow |
