| Extension | File Type | Files scanned | Contributor |
| M | MATLAB program | 19 | |
| M | Maple Common Binary file (generic) | 15 | |
| M01/P01/R01/S01 | MicroStation Modification resource file | 8 | |
| M15 | thinEdge model | 4 | |
| M3G | Mobile 3D Graphics | 8 | |
| M3U | Winamp Playlist File | 4 | .Cryorb |
| M3U8 | Audio Playlist (UTF-8) | 2 | |
| M4 | m4 preprocessor / macro source | 9 | |
| M4A | Apple Lossless Audio Codec | 20 | |
| M4A/MP4 | AAC Audio in MP4 container | 16 | |
| M4P | Protected iTunes Music Store audio track | 5 | |
| M4R | iPhone Ringtone | 464 | |
| M4V | MPEG-4 Video | 20 | |
| M64 | mupen64 movie capture | 2 | |
| M99 | M99 compressed data | 19 | Label |
| MA | Maya ASCII Scene | 17 | |
| MAB | Mozilla Address Book | 24 | |
| MAKI | Compiled Winamp Maki script | 51 | Josef Schneider |
| MANIFEST | Windows Manifest - Visual Stylesheet XML file | 19 | |
| MAP | Furcadia Map | 28 | |
| MAP | Gen Surf map | 6 | |
| MAP | Hex Workshop Char Map File | 6 | .Cryorb |
| MAP | MapInfo map | 21 | Rizla99 |
| MAP | Navigon map | 15 | |
| MAP | OziExplorer Map data | 30 | |
| MAR | MAr compressed archive | 5 | |
| MAR | Micrognosis compressed archive | 19 | Label |
| MAR | Microsoft(/MSN) MARC archive | 7 | |
| MAR | Mozilla ARchive | 6 | |
| MAS | Nascar SimRacing data | 2 | |
| MAT | 3D Studio Max Material Library | 36 | Alex Paven |
| MAT | Matlab Level 5 MAT-File | 5 | |
| MATHML | Mathematical Markup Language | 11 | Ryan Jones |
| MAX | 3D Studio Max Scene | 965 | Alex Paven |
| MAX | Creative Witer document | 24 | |
| MAX | PS2 PowerSave | 6 | |
| MAX | PaperPort scanned document/image | 8 | |
| MB | Maya Binary Scene | 43 | |
| MBD | Multimedia Builder Data | 3 | |
| MBF | Microsoft Money Backup file | 5 | |
| MBI | MBasic source | 4 | |
| MBM | SymbianOS Multi BitMap | 40 | |
| MBP | Mobipocket eBook Auxiliary data | 10 | |
| MBSA | Microsoft Baseline Security Analyser report | 12 | |
| MC4D/C4D | Maxon Cinema 4D v4.x object | 35 | |
| MC9 | Mastercam 9 geometry | 6 | |
| MCD | Bleem! memory card save game | 6 | |
| MCD | Mathcad document | 8 | |
| MCD | MiniCAD drawing | 29 | |
| MCD | VectorWorks Drawing | 50 | |
| MCF | MMS Composer File | 3 | |
| MCF | MasterCook Cookbook File | 4 | |
| MCF | Media Container Format stream | 2 | |
| MCF | TMPEGEnc config file | 14 | |
| MCL | Windows Media Center application link | 8 | |
| MCO | MSN Messenger Wink | 15 | |
| MCP | CodeWarrior Project | 23 | |
| MCP | MUSICompress encoded audio | 19 | |
| MCP | WaveZIP lossless compressed audio | 16 | |
| MCR | Musicator Delta song/music | 6 | |
| MCW | MacWrite II document | 15 | |
| MD | MDCD compressed archive | 7 | |
| MD | Mike Davies Music | 9 | |
| MD2 | Quake 2 model | 22 | |
| MD3 | Quake III Arena model | 6 | |
| MDA | MicroDesign Area bitmap | 3 | |
| MDA | Rays Media data | 2 | |
| MDB | Microsoft Jet DB | 50 | |
| MDD | MacDraft drawing | 11 | |
| MDF | Microsoft SQL Server 2000 database | 16 | Andreas |
| MDI | Microsoft Document Imaging format | 9 | |
| MDL | Digitrakker music module/song | 6 | Dr.Ryo(TM) |
| MDL | Half-life Model | 10 | |
| MDL | Microsoft Flight Simulator 3D model (generic) | 23 | |
| MDL | Mighty Draw DOS library | 67 | |
| MDL | MoRay 3D Model | 28 | |
| MDL | Simulink Model | 20 | |
| MDP | MicroDesign Page | 3 | |
| MDR | MagicDraw UML project | 8 | |
| MDS | Media Descriptor | 7 | |
| MDV | QLAY MDV image | 5 | |
| MDW | Microsoft Jet DB Workgroup Information | 6 | |
| MDX | MDict dictionary | 16 | |
| ME/MEW | Multi Edit configuration | 5 | |
| ME3 | Arcsoft MultiMedia Email 3.0 message | 9 | |
| MEB | Open eBook | 7 | |
| MED | MED/OctaMED Amiga module/song | 33 | Dr.Ryo(TM) |
| MEF | MAIET Encrypted File System | 2 | |
| MER | Entity-Relationship (ER) Diagram | 12 | |
| MET | HEC-HMS Metereologic model configuration | 5 | |
| MET | eMule *.part.met data/info | 8 | |
| METALINK | Metalink file | 34 | |
| MEX | Macro Express Macro | 10 | |
| MF | Java Manifest | 13 | |
| MFL | Mozilla XUL FastLoad File | 13 | |
| MFT | Battlefield Bad Company package manifest | 6 | |
| MGF | MalieGF bitmap | 2 | |
| MGF | Monarch Graphic File | 4 | |
| MHK | Broderbund Mohawk archive | 2 | |
| MHT | Microsoft Internet Explorer Web Archive | 112 | Dr.Ryo(TM) |
| MIA | MusicIndiaOnline Trident Player Music file | 2 | |
| MID | MIDI Music | 69 | |
| MIDNAM | MIDI patch name | 27 | |
| MIF | (Frame)Maker Interchange Format | 18 | |
| MIF | MapInfo Interchange Format | 5 | |
| MIFF | ImageMagick Machine independent File Format bitmap | 7 | |
| MIG | Mighty Draw drawing | 10 | |
| MIG | Windows Easy Transfer migration data | 2 | |
| MINIUSF | Nintendo Ultra 64 Sound Format | 386 | |
| MIO | MIO compressed audio | 7 | |
| MIO | MioMotion movie | 6 | |
| MIO | MyInfo Topic | 8 | |
| MIS | McGrath Information Solution metadata | 7 | |
| MITSU | Mitsubishi S340-10 bitmap | 40 | |
| MIX | Microsoft PhotoDraw drawing | 18 | |
| MIX | Project Dogwaffle mixing palette (type 2) | 15 | |
| MJP | J.River Media Center plugin | 22 | |
| MJP | VTech MJP video | 6 | |
| MJPG | SMJPEG Video | 2 | |
| MKV/MKA | Matroska stream | 7 | |
| MKW | mkwACT lossless compressed audio | 19 | |
| MLB | MyLittleBase database | 9 | |
| MLF | Package Download Profile | 3 | |
| MLI | AutoDesk 3D-Studio Material-Library | 3 | |
| MLP | Meridian Lossless Packing audio | 5 | |
| MLS | Skype localization data | 4 | |
| MM | FreeMind mind map | 15 | |
| MMAP | MindManager Brainstorm and Process Control Map | 4 | |
| MMD | Cumulate Draw's editable MMD format | 8 | |
| MMD | Madonna Model | 4 | |
| MMDC | MMDC Music | 14 | |
| MMF | Yamaha SMAF Synthetic music Mobile Application Format | 16 | |
| MMO | Hyper File memo | 43 | |
| MMO | Memory-Map Navigator Overlay | 40 | |
| MMP | Mindjet MindManager Map | 17 | |
| MMW | AceMoney data | 7 | |
| MND | Fractal Forge 2.x fractal parameters | 30 | |
| MNG | Multiple-image Network Graphics bitmap/anim | 2 | |
| MNY | Microsoft Money auto saved report | 2 | |
| MNY | Microsoft Money data | 8 | |
| MO3 | MO3 MOD audio format | 9 | |
| MOBI/PRC | Mobipocket - PRC Palm e-Book | 31 | |
| MOD | GoDot C64 Image Processing - Module | 31 | |
| MOD | Monarch model | 55 | |
| MODD | Picture Motion Browser data | 4 | |
| MODEL | CATIA model | 17 | |
| MODEL | LEGO model data | 43 | |
| MODEL | PlantWALK model | 3 | |
| MOL | MOdule (play)List | 2 | |
| MOL2 | Tripos Mol2 | 6 | |
| MON | M.O.N New Music | 16 | |
| MON | M.O.N Old Music | 5 | |
| MOP | NS/Elite Display 3.12 Macro Object Path File | 28 | Roberto 'rbnet' Bolli |
| MOU | WinMount archive | 6 | Ryan Jones |
| MOV | QuickTime Movie | 9 | |
| MP2S | Max Payne 2 saved game | 15 | |
| MP3 | AlbumWrap archive | 3 | |
| MP3 | AlbumWrap archive | 4 | |
| MP3 | GoGo encoded MP3 audio | 17 | |
| MP3 | GoGo encoded MP3 audio (ID3 v1.x tag) | 8 | |
| MP3 | GoGo encoded MP3 audio (ID3 v2.x tag) | 14 | |
| MP3 | LAME encoded MP3 audio | 7 | |
| MP3 | LAME encoded MP3 audio (ID3 v1.x tag) | 7 | |
| MP3 | LAME encoded MP3 audio (ID3 v2.x tag) | 9 | |
| MP3 | MP3 Xing Encoder | 28 | |
| MP3 | MP3 audio | 34 | |
| MP3 | MP3 audio (ID3 v1.x tag) | 21 | |
| MP3 | MP3 audio (ID3 v2.x tag) | 20 | |
| MP3 | Plugger encoded MP3 audio | 12 | |
| MP3 | mp3HD audio | 12 | |
| MP4 | Generic MP4 container | 16 | |
| MPB | MyPhoneExplorer Backup | 4 | |
| MPC | Musepack encoded audio (SV7.0) | 66 | |
| MPC | Musepack encoded audio (generic) | 114 | |
| MPCPL | MediaPlayer Classic playlist | 3 | |
| MPD | File List Creator list | 2 | |
| MPD | MapDraw chemical sequence map | 13 | |
| MPF | MainActor project | 17 | |
| MPG | MPEG2 Video File recorded by ProgDVB | 8 | THE LoW |
| MPG/MPEG | MPEG Video | 44 | |
| MPJ | Minitab project | 17 | |
| MPJ | Video Edit Magic project | 30 | |
| MPL | AVCHD Playlist | 6 | |
| MPLS | Blu-ray Movie Playlist Information | 3 | |
| MPN | Mophun game | 14 | |
| MPP | Microsoft Project | 43 | |
| MPQ | MPQ Archive - Blizzard game data | 2 | |
| MPS | Garmin MapSource data | 34 | |
| MPS | Max Payne 1 Savegame | 13 | dr. Angelo Amoruso |
| MPS | Microsoft Pocket Streets v8.0 (2004) Map | 16 | ptweasel |
| MPW/MPF | MosASCII Project Workspace | 3 | |
| MPZ | Moove Resource Description | 2 | |
| MPZ | SoundSlimmer compressed audio | 6 | |
| MQ4 | MetaQuote / MetaTrader indicator | 13 | |
| MQB | Metasequoia Brush | 2 | |
| MQL | MetaTrader indicator | 6 | |
| MQO | Metasequoia 3D scene | 28 | |
| MQP | Metasequoia Palette | 2 | |
| MQV | Sony Movie Player video | 37 | |
| MRK | CSI MaRKup drawing | 2 | |
| MRK | Informative Graphics Markup file | 8 | |
| MRP | MathRevolt Plot | 7 | |
| MRW | Minolta Dimage RAW image | 6 | |
| MS8/MS9/MS10 | MultiSim Design (generic) | 8 | |
| MSA | Atari MSA Disk Image | 18 | |
| MSC | Microsoft Management Console Snap-in control file | 18 | |
| MSCX | MuseScore document | 4 | |
| MSDVD | Windows DVD Maker project | 15 | |
| MSF | Mozilla Mail Summary file | 32 | |
| MSG | Outlook Message | 34 | |
| MSH | Fluent mesh | 7 | |
| MSH | Orbiter mesh | 33 | |
| MSI | Microsoft Windows Installer | 165 | |
| MSM | Windows Installer Merge Module | 12 | |
| MSO | ActiveMime object | 9 | |
| MSO | MedlySound module/song | 4 | |
| MSP | Microsoft Windows 2.x Paint bitmap | 20 | |
| MSP | Windows Installer Patch | 16 | |
| MSRCINCIDENT | Remote Assistance Request | 5 | |
| MST | Room Arranger design | 12 | |
| MST | Windows SDK Setup Transform Script | 15 | |
| MSWMM | Windows Movie Maker project | 12 | |
| MT2 | MadTracker 2.0 module / song | 6 | |
| MTD | Digital Sheet Music | 2 | |
| MTD | Digital Sheet Music (Big Endian) | 4 | |
| MTE | TargetExpress target | 598 | Hunter |
| MTF | Mediatek Font | 14 | |
| MTL | Alias|Wavefront material | 8 | |
| MTM | MultiTracker Module/song | 2 | |
| MTP | Minitab Portable Worksheet | 7 | |
| MTP | Power Translator document | 10 | |
| MTS | AVCHD video clips - MPEG Transport Stream | 6 | |
| MTS | JVC - Everio MPEG-2 Transprot Stream | 80 | boby |
| MTV | MTV video | 5 | |
| MTX | Matrix spreadsheet | 17 | |
| MTX | Viewpoint MetaStream scene | 7 | |
| MUP | Music Publisher score | 7 | |
| MUS | Doom/Heretic music | 6 | |
| MUS | Finale (generic binary format) | 22 | |
| MUS | Finale Guitar | 5 | |
| MUS | Finale NotePad | 8 | |
| MUS | Finale PrintMusic | 6 | |
| MUS | Finale music score | 10 | |
| MUS/ETF | Finale ETF Enigma Tansportable File | 6 | |
| MUS/MYR | Myriad Harmony / Melody assistant music | 24 | |
| MUSE | Emacs Muse project | 6 | |
| MV | Miva Script | 16 | |
| MV | SGI movie format | 7 | |
| MV3 | AUPEC encoded audio | 17 | |
| MVA | Setup Program Archive | 22 | |
| MVC | Collectorz.com Movie Collector data | 4 | |
| MVD | Magix Movie Edit video | 3 | |
| MVE | Interplay MVE video | 2 | |
| MVE | Wing Commander III MVE movie | 2 | |
| MVE | muvee autoProducer Project | 6 | |
| MVS | MusicMatch JukeBox Visualization (v1.0) | 11 | |
| MW | Maple XML worksheet | 18 | |
| MW2 | MicroWorlds LOGO Activity | 112 | |
| MW4 | MechWarrior 4 game data | 5 | |
| MWL | Mighty Draw Windows library | 3 | |
| MWS | Maple worksheet | 77 | |
| MXD | ArcMap GIS project | 35 | |
| MXD | MX series Remote Control configuration (generic) | 6 | |
| MXD | MX-850 Remote Control configuration | 4 | |
| MXL | Moxcel spreadsheet | 3 | |
| MXMF/XMF | MXMF Nokia Ringtone | 3 | |
| MXP | Macromedia Extension Package | 137 | Alex Paven |
| MXS | Maxwell Render Scene | 7 | |
| MXTX | MaxTrax Music | 59 | |
| MYI | MySQL Database 3.23.52 Index File | 89 | Roberto 'rbnet' Bolli |
| MYI | MySQL MyISAM tables index | 103 | |
| MYO | MYOB data | 4 | |
| MZ | MOZART Music Document | 36 | |
| MZF | MediaZip compressed archive | 10 | |
| MZX | MegaZeux world | 34 | flarn2006 |
