| mrk | Kodak EasyShare Job Definition |
| mrk | Pro/ENGINEER Markup File |
| mrm | CloseToSoftware MacroRunner Macro |
| mrp | Morphine Presets Data |
| mrp | Mythroad Platform Data |
| mrp | Xilinx MAP Report |
| mrpd | IBM TS3500 Machine Reported Product Data |
| mrq | NETFILE Tax Data |
| mrs | Clone Remover Data |
| mrs | Corel WordPerfect Macro Resource |
| mrsl | THOR Metadata Rich Spectral Library Data |
| mrt | Stimulsoft Report |
| mrv | Marvin Document Format File |
| mrx | Malete Record Access File |
| mry | Mercury Binary Crystal Data |
| mryx | Mercury Compressed XML Crystal Data |
| ms | Autodesk 3D Studio Max Script |
| ms | Maxwell Render Script |
| ms-one-stub | Microsoft OneNote Stub File |
| ms-tnef | MS Transport Neutral Encapsulation Format |
| ms1 | Crux MS/MS Data |
| ms2 | Crux MS/MS Data |
| ms2 | MADRIX Setup Data |
| ms2 | SEQUEST MS2 Format Data |
| ms4 | MAILERS+4 Index Data |
| msb | The Bat! Message Database |
| msbcm | Microsoft Office Business Contact Manager Backup Data |
| msbt | Nintendo Wii Galaxy Dialogue Data |
| msc | CRiSP Harvest Maturation Rate Parameters Data |
| msc | eYaMosaic Graphic Mosaic |
