File extensions beginning with the letter M. Commonly used extensions are listed in bold.

	M  A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z .m Mathematica Input File (more info) .m Objective-C Implementation File (more info) .m1a MPEG-1 Audio File (more info) .m1pg iFinish Video Clip (more info) .m1v MPEG-1 Video File (more info) .m2 World or Warcraft Model Object (more info) .m21 AXMEDIS MPEG-21 File (more info) .m21 MPEG-21 File (more info) .m2a MPEG-1 Layer 2 Audio File (more info) .m2p Maxthon 2 Browser Plugin File (more info) .m2s Maxthon 2 Browser Skin File (more info) .m2t HDV Video File (more info) .m2ts Blu-ray BDAV Video File (more info) .m2v MPEG-2 Video (more info) .m3d 3D Model File (more info) .m3g Mobile 3D Graphics Program (more info) .m3u Media Playlist File (more info) .m4 Macro Processor Library (more info) .m4a Apple Lossless Audio File (more info) .m4b MPEG-4 Audio Book File (more info) .m4e MPEG-4 Video File (more info) .m4p iTunes Music Store Audio File (more info) .m4r iPhone Ringtone File (more info) .m4u MPEG-4 Playlist (more info) .m4v iTunes Video File (more info) .ma Maya Project File (more info) .ma1 Monarch Audio File (more info) .mab Mozilla Address Book (more info) .mac MacPaint Image (more info) .mad Access Module (more info) .maf Microsoft Access Form (more info) .mag Magic Circuit Layout (more info) .mag Access Diagram (more info) .magik Magik Source Code File (more info) .mai Microsoft Mail File (more info) .mailhost MSN Mailhost Settings File (more info) .mak Makefile (more info) .mam Microsoft Access Macro (more info) .man Unix Manual (more info) .manifest Windows Visual Styles File (more info) .map Weather Defender Map (more info) .map Image Map (more info) .map Half-Life Map File (more info) .mapimail Send To Mail Recipient (more info) .maq Microsoft Access Query (more info) .mar Microsoft Access Report (more info) .mas Access Stored Procedures (more info) .master ASP.NET Master Page (more info) .mat MATLAB Variables Binary File (more info) .mat Microsoft Access Table (more info) .mat V-Ray Materials File (more info) .mato Atomic Combat Saved Game (more info) .mau Media Attachment Unit (more info) .mav Access View File (more info) .maw Access Data Access Page (more info) .max PaperPort Scanned Document (more info) .max 3ds Max Scene File (more info) .max Action Replay Max Save File (more info) .max OmniPage Scanned Document (more info) .mb Maya Binary Project File (more info) .mbg Mailbag Assistant Mailbox File (more info) .mbg Microsoft Mailbag (more info) .mbi Multi-Bootable Information File (more info) .mbl Logger Pro Data File (more info) .mbm Multi Bitmap File (more info) .mbox E-mail Mailbox File (more info) .mbp Mobipocket Notes File (more info) .mbx Outlook Express Mailbox (more info) .mc1 MedCalc Data File (more info) .mc5 Poser 5 Material File (more info) .mc6 Poser 6 Material File (more info) .mc9 Mastercam 9 Geometry File (more info) .mcd Mathcad Document (more info) .mcfi Maya Initial Fluid Cache File (more info) .mcfp Maya Fluid Cache Playback File (more info) .mci Media Control Interface (more info) .mco Live Messenger Winks File (more info) .mcr 3ds Max Macroscript File (more info) .mcs Mathcad Image (more info) .mcx MICRO CADAM-X/6000 Model Data File (more info) .mcz Compressed Poser Material File (more info) .md MDCD Compressed Archive (more info) .md Moneydance Financial Data File (more info) .md Machine Description File (more info) .md0 Alcohol Disk Image Segment 1 (more info) .md1 GEAR CD/DVD Disc Image (more info) .md1 Alcohol Disk Image Segment 2 (more info) .md2 Alcohol Disk Image Segment 2 (more info) .md2 Quake 2 Player Model (more info) .md3 Quake III 3D Model (more info) .md5 MD5 Checksum File (more info) .mda Access Add-in (more info) .mdb Microsoft Access Database (more info) .mdc Multi Dimension Cube File (more info) .mde ArchiCAD Educational Version Module File (more info) .mde Access Add-in (Compiled) (more info) .mdf SQL Server Database File (more info) .mdf Translation Memory Data Find File (more info) .mdf Media Disc Image File (more info) .mdf Measurement Data Format File (more info) .mdi Microsoft Document Imaging File (more info) .mdl Half-Life Model File (more info) .mdl DigiTrakker Module (more info) .mdl Rational Rose Model File (more info) .mdl Simulink Model File (more info) .mdl Flight Simulator Airplane Model (more info) .mdmp Windows Minidump (more info) .mdn Blank Access Database Template (more info) .mds Media Descriptor File (more info) .mds Alcohol Disc Image Track Data (more info) .mdt Access Database Template (more info) .mdw Access Workgroup File (more info) .mdx Rational XDE Model File (more info) .mdx Multiple Index File (more info) .mdz Access Wizard Template (more info) .me Readme Text File (more info) .meb PRO100 3D Interior Catalog Element (more info) .med Amiga MED Sound File (more info) .med RSView Development Project (more info) .mel Maya Embedded Language File (more info) .mell Mellel Word Processing File (more info) .mellel Mellel Word Processing Document (more info) .mem Virtual Game Station Memory File (more info) .mem FoxPro Variable File (more info) .mem Macro Editor Macro (more info) .mem Mnemosyne Card Collection (more info) .mer RSView Development Runtime File (more info) .mesh 3D Mesh Model (more info) .meta RealPlayer Metafile (more info) .metadata_never_index Spotlight Never Index File (more info) .mex Macro Express File (more info) .mf Java Manifest File (more info) .mfa Multimedia Fusion Development File (more info) .mfo MediaFace Online Saved File (more info) .mfo Perl ModInfo Descriptor File (more info) .mfp Macromedia FlashPaper Document (more info) .mfp MediaFACE Project File (more info) .mfs MetFS Encrypted File System (more info) .mft MediaFACE Project Template (more info) .mfx Multimedia Fusion Extension (more info) .mgc MGCSoft Equation Illustrator File (more info) .mgf Materials and Geometry Format (more info) .mgl Age of Empires 2 Replay File (more info) .mgm MGCSoft Equation Illustrator Macro (more info) .mgs MGCSoft Vector Shapes (more info) .mgv Yamaha MegaVoice File (more info) .mgv PSP Video File (more info) .mgx Rise of Nations Saved Game (more info) .mgx Age of Empires 2 Expansion Replay File (more info) .mhs Hardware Specification File (more info) .mht MHTML Web Archive (more info) .mhtml MIME HTML File (more info) .mic Image Composer File (more info) .mid MIDI File (more info) .midi MIDI File (more info) .mif Management Information Format (more info) .milk MilkDrop Winamp Plugin Preset (more info) .mim Multi-Purpose Internet Mail Message (more info) .mime Multi-Purpose Internet Mail Extension (more info) .miniusf Nintendo 64 Song File (more info) .mint Linux Mint Installer File (more info) .mip Multiple Image Print File (more info) .mis Saved Game Mission File (more info) .mis Marble Blast Gold Mission File (more info) .mix PhotoDraw Image File (more info) .mix Picture It! Image File (more info) .mix Command & Conquer Data File (more info) .mj2 Motion JPEG 2000 Video Clip (more info) .mjp MJPEG Video File (more info) .mjpg Motion JPEG Video File (more info) .mk Makefile (more info) .mka Matroska Audio File (more info) .mkv Matroska Video File (more info) .mlk Mastercook Look File (more info) .mls CrystalPlayer Playlist (more info) .mls Milestones Simplicity File (more info) .mm FreeMind Mind Map (more info) .mm6 Might and Magic 6 Saved Game (more info) .mm7 Might and Magic 7 Saved Game (more info) .mm8 Might and Magic 8 Saved Game (more info) .mma Master Album Maker Digital Photo Album (more info) .mmap MindManager Map File (more info) .mmc Microsoft Media Catalog (more info) .mme Multi-Purpose Internet Mail (more info) .mmf Synthetic Music Mobile Application File (more info) .mmf Microsoft Message File (more info) .mmo Memory Map Overlay File (more info) .mmp Master Album Maker Project (more info) .mmp MixMeister Playlist (more info) .mmp MindManager Mind Map (more info) .mnc My Notes Center Notebook (more info) .mng Yamaha PSR Disk Manager File (more info) .mng Multiple Network Graphic (more info) .mnk My Notes Keeper Notebook (more info) .mnm Character Studio Marker Name File (more info) .mno Macromedia Design Note (more info) .mnt FoxPro Menu Memo (more info) .mnv PlayStation Movie File (more info) .mnx FoxPro Menu (more info) .mny Microsoft Money File (more info) .mo Machine Object File (more info) .mo3 MO3 Audio File (more info) .mobi Mobipocket eBook (more info) .mod ArchiCAD Module (more info) .mod Amiga Music Module File (more info) .mod JVC Recorded Video File (more info) .mod Fortran Module File (more info) .modd Sony Video Analysis File (more info) .model CATIA 3D Model FIle (more info) .moho Anime Studio Animation Project (more info) .mom Managed Object Model (more info) .moov Apple QuickTime Movie (more info) .mosaic MacOSaiX Mosaic File (more info) .mov Apple QuickTime Movie (more info) .movie QuickTime Movie File (more info) .mox ExtendSim Simulation Software Model (more info) .moz Mozilla Cache File (more info) .mp Maya PLE Project File (more info) .mp1 MPEG-1 Layer 1 Audio File (more info) .mp2 MPEG Layer II Compressed Audio File (more info) .mp21 AXMEDIS MPEG-21 Object (more info) .mp21 MPEG-21 Multimedia File (more info) .mp2m Max Payne 2 Mod File (more info) .mp2s Max Payne 2 Saved Game (more info) .mp2v MPEG-2 Video File (more info) .mp3 MP3 Audio File (more info) .mp4 MPEG-4 Video File (more info) .mp4v MPEG-4 Video (more info) .mpa MPEG-2 Audio File (more info) .mpc Musepack Compressed Audio File (more info) .mpcpl Media Player Classic Playlist (more info) .mpd File List Creator Playlist (more info) .mpe MPEG Movie File (more info) .mpeg MPEG Movie (more info) .mpg MPEG Video File (more info) .mpg2 MPEG-2 Video File (more info) .mpga MPEG-1 Layer 3 Audio File (more info) .mpk Project64 Memory Pack File (more info) .mpkg Meta Package File (more info) .mpm Max Payne Modfication File (more info) .mpp Microsoft Project File (more info) .mpq Blizzard Mo'PaQ File (more info) .mpr FoxPro Generated Menu Program (more info) .mps Pocket Streets Map File (more info) .mps Max Payne Saved Game (more info) .mpt Microsoft Project Template (more info) .mpu MPEG Layer 3 Audio File (more info) .mpv2 MPEG-2 Video Stream (more info) .mpx Microsoft Project Exchange File (more info) .mpx FoxPro Compiled Menu Program (more info) .mp_ Mobile Phone Sound File (more info) .mq4 MetaTrader Custom Indicator (more info) .mqv Sony Movie Format File (more info) .mrb Multiple Resolution Bitmap (more info) .mrc mIRC Script File (more info) .mrk DPOF Auto Print Order File (more info) .mrs GunZ Game Data File (more info) .mrw Minolta Raw Image File (more info) .ms 3ds Max Script File (more info) .ms-tnef MS Transport Neutral Encapsulation Format (more info) .ms10 Multisim Circuit Design (more info) .ms3d MilkShape 3D Model (more info) .msc Microsoft Management Console Snap-in Control File (more info) .msdvd Windows DVD Maker Project File (more info) .mse 3ds Max Encrypted MAXScript File (more info) .msf Mail Summary File (more info) .msf Miranda IM Skin File (more info) .msg Mail Message (more info) .msh Visual Communicator Project File (more info) .msi Windows Installer Package (more info) .msk Paint Shop Pro Mask (more info) .mskn MediaMonkey Skin File (more info) .msm Windows Installer Merge Module (more info) .msn Host Blocking File (more info) .mso Microsoft Office Macro Reference File (more info) .mso Inline E-mail Attachment (more info) .msp Windows Installer Patch (more info) .msp Microsoft Paint Bitmap Image (more info) .mspx Microsoft ASP.NET Web Page (more info) .mss Software Specification File (more info) .msstyle Windows XP Unsigned Style (more info) .msstyles Windows XP Style (more info) .mst Windows SDK Setup Transform Script (more info) .msu Windows Vista Update Package (more info) .msv Memory Stick Voice File (more info) .mswmm Windows Movie Maker Project (more info) .mt2 MadTracker 2 Module (more info) .mte MadTracker 2 Envelope (more info) .mtf Motorola Theme File (more info) .mtf Translation Memory Translations File (more info) .mtf MasterCook Tips (more info) .mth Derive Math File (more info) .mti MadTracker Instrument (more info) .mtm MultiTracker Module (more info) .mtp MadTracker 2 Pattern (more info) .mts MadTracker 2 Sample File (more info) .mts AVCHD Video File (more info) .mtv MTV Video Format File (more info) .mtx MetaStream Scene File (more info) .mtx MadTracker 2 Extension (more info) .mtz Compressed MetaStream Scene File (more info) .mud Textease Multi User Database (more info) .mui MultiLanguage Resource File (more info) .mum Windows Vista Update Package (more info) .mus Finale Notation File Format (more info) .mus Playstation 2 Music File (more info) .mvb Multimedia Viewer Book Source File (more info) .mvc Movie Collector Catalog (more info) .mvd Movie Edit Pro Video Project (more info) .mvi AutoCAD Movie Command File (more info) .mvs Project Language and Simulation File (more info) .mvx Multimedia Fusion Movement Extension (more info) .mw MacWrite Text Document (more info) .mw Maple Worksheet (more info) .mwd MarinerWrite Document (more info) .mwf Translation Memory Word Find File (more info) .mwp Lotus Word Pro SmartMaster File (more info) .mws MWave DSP Synth Instrument Extract (more info) .mws Maple Classic Worksheet (more info) .mxd ArcGIS Map Document (more info) .mxe Macro Express Playable Macro (more info) .mxml Flex MXML Component (more info) .mxp Macromedia Extension (more info) .myapp Visual Studio Application XML File (more info) .myd MySQL Database Data File (more info) .mydocs Send To My Documents (more info) .myi MySQL MyISAM Index File (more info) .mzp MAXScript Zip Package (more info) .mzp Mozart Percussion File (more info)

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