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