| m64 | Mupen64 Movie Capture |
| m6b | Speedtronic Mark VI Data |
| m77t | GEODAS MGD77T Data |
| m7a | MapKing Map Data |
| m7c | Yamaha M7CL Digital Mixing Console Data |
| m98 | Nokia Mediamaster 9800S Satellites Data |
| m99 | MicroStation Modification User Resource File |
| maa | MMANA Antenna Data |
| mab | Mozilla Address Book |
| mac | Minitab Macro Data |
| mac | PATCHMASTER Macro File |
| mac | SmartWare Macro File |
| macbin | Macbinary Encoded |
| macro | Tecplot 360 Macro Data |
| macs | MADRIX Encrypted Script |
| mad | Microsoft Access Module Shortcut |
| mads | Metadata Authority Description Schema Data |
| magiwol | MagiWOL Data |
| mai | Pegasus Mail Sub Directory |
| mail | NeoPlanet Mail Data |
| maildb | MSN Mail Database |
| mailloc | Mac OS X Finder Mail Internet Location |
| mailstationery | Apple Mail Stationery Data |
| mailtoloc | Mac OS X Finder Mail Internet Location |
| mailview | Microsoft Mail View Data |
| main | FileMaker Pro Dictionary Data |
| maj | CAMduct Job Data |
| maker | Adobe FrameMaker Data |
| mamc | Auto Mouse Click Script |
| maml | Microsoft Assistance Markup Language Data |
| mamp | MAMP Related Data |
| man | AquaCrop Field Management Data |
| map | Hex Workshop Character Map |
| map | Ingres Termcap Mapping Data |
| map | Leadwerks Map Data |
