| m12 | Microsoft Money 2004 Backup Data |
| m12 | Schiller Medilog 12ch ECG Raw Data |
| m14 | Microsoft Money 2005 Backup Data |
| m15 | Microsoft Money 2006 Backup Data |
| m16 | Microsoft Money 2007 Backup Data |
| m1c | IBM Voice Type Languages Newuser Data |
| m1i | IBM Voice Type Languages Newuser Data |
| m2 | Juki AMS Embroidery Data |
| m21 | AXMEDIS MPEG21 Data |
| m25 | Symantec Endpoint Protection Manager Data |
| m2c | IBM Voice Type Languages Newuser Data |
| m2d | HTC Manila 2D Skin |
| m2d | SNMP v2c MIB Data |
| m2dct | Manila 2D for Windows Mobile Skin Data |
| m2f | Maxthon 2 Browser Filter |
| m2i | IBM Voice Type Languages Newuser Data |
| m2l | Maxthon 2 Language Pack |
| m2p | GROMACS Mat2PS Data |
| m2p | Maxthon 2 Browser Plugin |
| m2r | Micromuse Mib2Rules Data |
| m2s | Maxthon 2 Browser Skin |
| m2u | Maxthon 2 Browser Layout Data |
| m3 | Juki AMS Embroidery Data |
| m3c | IBM Voice Type Languages Newuser Data |
| m3d | DIALux 3D Model Data |
| m3d | DJ Mix Pro Database |
| m3i | IBM Voice Type Languages Newuser Data |
| m3r | Autodesk Moldflow 3D Fill+Pack Restart File |
| m3x | MAGIX Digital Foto Maker PhotoCD Playlist Data |
| m4c | IBM Voice Type Languages Newuser Data |
| m4d | Sage MAS 90 Data File |
| m4i | IBM Voice Type Languages Newuser Data |
| m4p | Sage MAS 90 Program File |
| m4t | Sage MAS 90 Table File |
| m5p | MachFive Preset Data |
