Alphabetically: M
Extension File Description File Type
.m
Objective-C Implementation File
Developer
.m15
MPEG Video
Video
.m1a
MPEG-1 Audio File
Audio
.m1pg
iFinish Video Clip
Video
.m1v
MPEG-1 Video File
Video
.m2
World or Warcraft Model Object
Game
.m21
MPEG-21 File
Video
.m2a
MPEG-1 Layer 2 Audio File
Video
.m2p
MPEG-2 Program Stream File
Video
.m2s
Maxthon 2 Browser Skin File
Settings
.m2t
HDV Video File
Video
.m2ts
Blu-ray BDAV Video File
Video
.m2v
MPEG-2 Video
Video
.m3
Blizzard MDX3 Model File
3D Image
.m3d
3D Model File
3D Image
.m3g
Mobile 3D Graphics Program
Executable
.m3u
Media Playlist File
Audio
.m3u8
UTF-8 M3U Playlist File
Audio
.m4
Macro Processor Library
Developer
.m4a
Apple Lossless Audio File
Audio
.m4b
MPEG-4 Audio Book File
Audio
.m4e
MPEG-4 Video File
Video
.m4p
iTunes Music Store Audio File
Audio
.m4r
iPhone Ringtone File
Audio
.m4u
MPEG-4 Playlist
Video
.m4v
iTunes Video File
Video
.m75
MPEG Video
Video
.ma
Maya Project File
3D Image
.ma1
Monarch Audio File
Audio
.mab
Mozilla Address Book
Misc
.mac
MacPaint Image
Raster Image
.macbin
Macbinary Encoded File
Data
.mad
Access Module
Misc
.mae
My Avatar Editor Character File
Game
.maf
Microsoft Access Form
Database
.maff
Mozilla Archive Format File
Web
.mag
Access Diagram Shortcut File
Misc
.magik
Magik Source Code File
Developer
.mai
Microsoft Mail File
Data
.mailhost
MSN Mailhost Settings File
Settings
.mak
Makefile
Developer
.mam
Microsoft Access Macro
Executable
.man
Unix Manual
Text
.manifest
Windows Visual Styles File
System
.manm
Vietcong Game Data File
Game
.map
Quake Engine Map File
Game
.mapimail
Send To Mail Recipient
System
.maq
Microsoft Access Query
Database
.mar
Microsoft Access Report
Misc
.mars
Adobe MARS File
Layout
.marshal
Marshal Data Migration Model File
Database
.mas
Access Stored Procedures
Database
.masseffectprofile
Mass Effect Player Profile
Game
.masseffectsave
Mass Effect Saved Game
Game
.master
ASP.NET Master Page
Web
.mat
MATLAB MAT-File
Data
.material
Rigs of Rods Texture Reference File
Settings
.mato
Atomic Combat Saved Game
Game
.mau
Media Attachment Unit
Misc
.mav
Access View File
Database
.maw
Access Data Access Page
Misc
.max
3ds Max Scene File
3D Image
.mb
Maya Binary Project File
3D Image
.mbb
Kodak EasyShare Data File
Misc
.mbbk
ManaBook Book Kit File
Layout
.mbf
Microsoft Money Backup File
Data
.mbg
Mailbag Assistant Mailbox File
Data
.mbi
Multi-Bootable Information File
Disk Image
.mbl
Logger Pro Data File
Data
.mbm
Multi Bitmap File
Raster Image
.mbox
E-mail Mailbox File
Text
.mbp
Mobipocket Notes File
Data
.mbr
Master Boot Record File
System
.mbs
Opera Mailbox File
Misc
.mbx
Outlook Express Mailbox
Data
.mc1
MedCalc Data File
Data
.mc2
MasterCook 5 Cookbook File
Misc
.mc5
Poser 5 Material File
3D Image
.mc6
Poser 6 Material File
3D Image
.mc9
Mastercam 9 Geometry File
CAD
.mcd
Mathcad Document
Data
.mcf
MasterCook 2 Cookbook File
Misc
.mcfi
Maya Initial Fluid Cache File
Misc
.mcfp
Maya Fluid Cache Playback File
Misc
.mci
Media Control Interface
Misc
.mcl
Windows Media Center Link File
Settings
.mclevel
Minecraft Map File
Game
.mco
Live Messenger Winks File
Misc
.mcr
3ds Max Macroscript File
Executable
.mcrp
MobyExplorer Encrypted File
Encoded
.mcs
Mathcad Image
Raster Image
.mcw
Monitor Calibration Wizard File
Settings
.mcx
MICRO CADAM-X/6000 Model Data File
CAD
.mcxe
MedicinesComplete Data File
Data
.mcz
Compressed Poser Material File
3D Image
.md
Moneydance Financial Data File
Data
.md0
Alcohol Disk Image Segment 1
Disk Image
.md1
GEAR CD/DVD Disc Image
Disk Image
.md2
Quake 2 Player Model
Game
.md3
Quake 3 3D Model
Game
.md5
MD5 Checksum File
Misc
.md5anim
id Tech 4 Model Animation File
3D Image
.md5camera
id Tech 4 Model Camera File
3D Image
.md5mesh
id Tech 4 3D Mesh File
3D Image
.md8
GarageCUBE Modul8 Project
Data
.mda
Access Add-in
Plugin
.mdb
Microsoft Access Database
Database
.mdbackup
iPhone Data Backup File
Backup
.mdbhtml
Microsoft Access Database HTML File
Database
.mdc
Multi Dimension Cube File
Data
.mddata
iPhone Backup File
Backup
.mde
Access Add-in (Compiled)
Plugin
.mdf
Media Disc Image File
Disk Image
.mdi
Microsoft Document Imaging File
Layout
.mdinfo
iPhone Backup Information File
Backup
.mdl
Warcraft 3 3D Model Text File
3D Image
.mdm
HLM Multivariate Data Matrix File
Data
.mdmp
Windows Minidump
System
.mdn
Blank Access Database Template
Database
.mdp
Visual C++ 5 Workspace File
Settings
.mds
Media Descriptor File
Disk Image
.mdt
Access Database Template
Database
.mdw
Access Workgroup File
Misc
.mdx
Warcraft 3 Model File
3D Image
.mdz
Access Wizard Template
Data
.me
Readme Text File
Text
.me2mod
Mass Effect 2 Modification File
Game
.meb
PRO100 3D Interior Catalog Element
3D Image
.med
Amiga MED Sound File
Audio
.mef
Mamiya RAW Image
Raster Image
.mel
Maya Embedded Language File
Executable
.mell
Mellel Word Processing File
Text
.mellel
Mellel Word Processing Document
Text
.mem
Macro Editor Macro
Executable
.menc
Windows Mobile Encrypted File
Data
.menu
Quake 3 Engine Menu File
Game
.mer
RSView Development Runtime File
Developer
.mesh
3D Mesh Model
3D Image
.met
eMule Resource File
Data
.meta
RealPlayer Metafile
Video
.metadata_never_index
Spotlight Never Index File
System
.mex
Macro Express File
Data
.mf
Java Manifest File
Developer
.mfa
Multimedia Fusion Development File
Developer
.mfe
MobileFrame Enterprise Data File
Data
.mfo
Perl ModInfo Descriptor File
Data
.mfp
Macromedia FlashPaper Document
Data
.mfs
MetFS Encrypted File System
Encoded
.mft
MediaFACE Project Template
Layout
.mfu
MobileFrame Update File
Data
.mfv
MobileFrame Device Pack File
Data
.mfw
MobileFrame Workflow Pack File
Plugin
.mfx
Multimedia Fusion Extension
Plugin
.mga
Manga Document
Layout
.mgc
MGCSoft Equation Illustrator File
Data
.mgcb
Equation Illustrator Project File
Vector Image
.mgdatabase
MacGourmet Deluxe Database File
Misc
.mgf
Materials and Geometry Format
3D Image
.mgl
Age of Empires 2 Replay File
Game
.mgm
MGCSoft Equation Illustrator Macro
Settings
.mgo
MacGourmet Recipe File
Misc
.mgs
MGCSoft Vector Shapes File
Vector Image
.mgt
Musicnotes Guitar Guru Song File
Misc
.mgtheme
MacGourmet Theme File
Settings
.mgv
PSP Video File
Video
.mgx
Age of Empires 2 Expansion Replay File
Game
.mhs
Hardware Specification File
Misc
.mht
MHTML Web Archive
Web
.mhtml
MIME HTML File
Web
.mi4
Audio Player Firmware File
System
.mic
Image Composer File
Raster Image
.mid
MIDI File
Audio
.midi
MIDI File
Audio
.mif
FrameMaker Interchange Format File
Layout
.mig
Windows Migration Backup File
Backup
.mii
Wii Virtual Avatar File
Game
.milk
MilkDrop Winamp Plugin Preset
Plugin
.mim
Multi-Purpose Internet Mail Message File
Encoded
.mime
Multi-Purpose Internet Mail Extension
Encoded
.mine
Minecraft Map File
Game
.miniusf
Nintendo 64 Song File
Audio
.mint
Linux Mint Installer File
Compressed
.mio
MioEngine Application File
Executable
.mip
Multiple Image Print File
Raster Image
.mis
Saved Game Mission File
Game
.mission
MissionMaker Project File
Data
.mix
Microsoft Image Exchange File
Raster Image
.mj2
Motion JPEG 2000 Video Clip
Video
.mjd
Adobe Acrobat MIME Encoded Job Definition File
Encoded
.mjdoc
MacJournal Document
Misc
.mjp
MJPEG Video File
Video
.mjpg
Motion JPEG Video File
Video
.mk
Makefile
Developer
.mka
Matroska Audio File
Audio
.mkv
Matroska Video File
Video
.ml
ML Source Code File
Developer
.mlb
Visual FoxPro Library
Developer
.mlc
Microsoft Language Interface Pack
System
.mlk
Mastercook Look File
Settings
.mlp
Meridian Lossless Packing Audio File
Audio
.mls
Milestones Simplicity File
Data
.mm
FreeMind Mind Map
Data
.mm6
Might and Magic 6 Saved Game
Game
.mm7
Might and Magic 7 Saved Game
Game
.mm8
Might and Magic 8 Saved Game
Game
.mma
Master Album Maker Photo Album File
Data
.mmap
MindManager Map File
Data
.mmat
MindManager Map Template
Vector Image
.mmc
Microsoft Media Catalog
Data
.mme
Multi-Purpose Internet Mail
Encoded
.mmf
Synthetic Music Mobile Application File
Audio
.mml
FrameMaker Maker Markup Language File
Layout
.mmm
MAGIX Music Maker File
Audio
.mmo
Memory Map Overlay File
Misc
.mmp
Symbian Project Specification File
Settings
.mmu
myPM Merge Data File
Data
.mmv
MicroMV Video File
Video
.mnc
My Notes Center Notebook
Data
.mng
Multiple Network Graphic
Raster Image
.mnh
Master Navigator Header File
GIS
.mnk
My Notes Keeper Notebook
Data
.mnl
AutoCAD Menu LISP File
Misc
.mnm
Character Studio Marker Name File
3D Image
.mno
Macromedia Design Note
Data
.mnr
AutoCAD Menu Resource File
Raster Image
.mns
AutoCAD Interface Settings File
Settings
.mnt
FoxPro Menu Memo
Text
.mnu
AutoCAD Interface Layout File
Settings
.mnv
PlayStation Movie File
Video
.mnx
FoxPro Menu
Misc
.mny
Microsoft Money File
Data
.mo
Machine Object File
Developer
.mo3
MO3 Audio File
Audio
.mobi
Mobipocket eBook
Data
.mobileconfig
Apple Mobile Configuration File
System
.mod
Amiga Music Module File
Audio
.modd
Sony Video Analysis File
Video
.model
CATIA 3D Model FIle
CAD
.mof
Managed Object Format File
Settings
.moff
Sony Video Analysis Index File
Video
.moho
Anime Studio Animation Project
Data
.moi
MOI Video File
Video
.mom
Managed Object Model
Developer
.montage
Montage Screenplay File
Misc
.moov
Apple QuickTime Movie
Video
.mos
Leaf Camera RAW File
Raster Image
.mosaic
MacOSaiX Mosaic File
Data
.mou
WinMount Compressed File
Compressed
.mov
Apple QuickTime Movie
Video
.movie
QuickTime Movie File
Video
.mox
ExtendSim Simulation Software Model
Data
.moz
Mozilla Cache File
Web
.mp
Maya PLE Project File
3D Image
.mp1
MPEG-1 Layer 1 Audio File
Audio
.mp2
MPEG Layer II Compressed Audio File
Audio
.mp21
MPEG-21 Multimedia File
Video
.mp2m
Max Payne 2 Mod File
Game
.mp2s
Max Payne 2 Saved Game
Game
.mp2v
MPEG-2 Video File
Video
.mp3
MP3 Audio File
Audio
.mp4
MPEG-4 Video File
Video
.mp4v
MPEG-4 Video
Video
.mpa
MPEG-2 Audio File
Audio
.mpb
MyPhoneExplorer Backup File
Backup
.mpc
Musepack Compressed Audio File
Audio
.mpcpl
Media Player Classic Playlist
Misc
.mpd
Microsoft Project Database
Database
.mpdconf
Music Player Daemon File
Settings
.mpe
MPEG Movie File
Video
.mpeg
MPEG Movie
Video
.mpeg4
MPEG-4 File
Video
.mpf
Microsoft Media Package FIle
Raster Image
.mpg
MPEG Video File
Video
.mpg2
MPEG-2 Video File
Video
.mpga
MPEG-1 Layer 3 Audio File
Audio
.mpgindex
Adobe MPEG Index File
Video
.mpj
Minitab Project File
Data
.mpk
ArcGIS Map Package
GIS
.mpkg
Meta Package File
Compressed
.mpl
AVCHD Playlist File
Video
.mpls
Blu-ray Movie Playlist File
Video
.mpm
Max Payne Modfication File
Game
.mpp
Microsoft Project File
Data
.mpq
Blizzard Mo'PaQ File
Game
.mpr
FoxPro Generated Menu Program
Developer
.mps
Pocket Streets Map File
GIS
.mpsub
MPlayer Subtitles File
Video
.mpt
Microsoft Project Template
Data
.mpu
MPEG Layer 3 Audio File
Audio
.mpv
MPEG Elementary Stream Video File
Video
.mpv2
MPEG-2 Video Stream
Video
.mpw
Microsoft Project Workspace File
Settings
.mpx
FoxPro Compiled Menu Program
Executable
.mpz
Miradi Project File
Data
.mp_
Mobile Phone Sound File
Audio
.mq4
MetaTrader Custom Indicator
Data
.mqv
Sony Movie Format File
Video
.mrb
Multiple Resolution Bitmap File
Raster Image
.mrc
mIRC Script File
Executable
.mrimg
Macrium Reflect Disk Image
Disk Image
.mrk
DPOF Auto Print Order File
Misc
.mrml
3D Slicer Scene Description File
3D Image
.mrs
GunZ Game Data File
Game
.mrw
Minolta Raw Image File
Raster Image
.ms
3ds Max Script File
Executable
.ms-tnef
MS Transport Neutral Encapsulation Format
Misc
.ms10
Multisim Circuit Design
Data
.ms3d
MilkShape 3D Model
3D Image
.ms8
Multisim Circuit Design File
Data
.msc
Microsoft Management Console Snap-in Control File
System
.mscx
MuseScore Music Score File
Audio
.mscz
MuseScore Compressed Score File
Audio
.msdvd
Windows DVD Maker Project File
Video
.mse
3ds Max Encrypted MAXScript File
Encoded
.msf
Mail Summary File
Misc
.msg
Outlook Mail Message
Text
.msh
Visual Communicator Project File
Video
.msi
Windows Installer Package
Misc
.msk
Paint Shop Pro Mask File
Raster Image
.mskn
MediaMonkey Skin File
Settings
.msm
Windows Installer Merge Module
Settings
.msn
Host Blocking File
Settings
.mso
Inline E-mail Attachment
Misc
.msp
Windows Installer Patch
System
.mspx
Microsoft ASP.NET Web Page
Web
.msrcincident
Windows Remote Assistance Invitation File
Misc
.mss
Microprocessor Software Specification File
Developer
.msstyle
Windows XP Unsigned Style
System
.msstyles
Windows XP Style
System
.mst
Windows SDK Setup Transform Script
Executable
.msu
Windows Vista Update Package
Misc
.msv
Memory Stick Voice File
Audio
.mswmm
Windows Movie Maker Project
Video
.mt2
MadTracker 2 Module
Audio
.mt9
MT9 Audio File
Audio
.mtd
Musicnotes Digital Sheet Music File
Misc
.mte
MadTracker 2 Envelope
Audio
.mtf
Motorola Theme File
Settings
.mth
Derive Math File
Data
.mti
MadTracker Instrument
Audio
.mtl
OBJ Material File
3D Image
.mtm
MultiTracker Module
Audio
.mtp
MadTracker 2 Pattern
Audio
.mts
AVCHD Video File
Video
.mtv
MTV Video Format File
Video
.mtw
Minitab Worksheet File
Data
.mtx
MadTracker 2 Extension
Plugin
.mtz
Compressed MetaStream Scene File
3D Image
.mud
Textease Multi User Database
Database
.muf
Alpha Five Licence File
Data
.mui
Multilingual User Interface File
System
.mum
Windows Vista Update Package
System
.mus
Finale Notation File Format
Audio
.musa
Aleph One Music File
Audio
.mv
MivaScript File
Developer
.mvb
Multimedia Viewer Book Source File
Video
.mvc
MivaScript Compiled File
Web
.mvd
Movie Edit Pro Movie File
Video
.mve
Infinity Engine Movie File
Video
.mvi
AutoCAD Movie Command File
Misc
.mvp
Movie Edit Pro Video Project File
Video
.mvr
IBM HotMedia Multimedia File
Web
.mvs
Project Language and Simulation File
Misc
.mvx
Multimedia Fusion Movement Extension
Developer
.mvy
Video easy Project File
Video
.mv_
Movie Edit Pro Movie Backup File
Backup
.mw
Maple Worksheet
Data
.mwd
MarinerWrite Document
Text
.mwf
MapGuide Author Map Window File
Data
.mwp
Lotus Word Pro SmartMaster File
Text
.mws
Maple Classic Worksheet
Data
.mwx
MapGuide Author Map Window XML File
GIS
.mx
Mathematica Serialized Package File
Data
.mxad
Mandelbrot Explorer All Data File
Data
.mxc2
MAGIX Cache File
Data
.mxcs
Mandelbrot Explorer Color Scheme File
Settings
.mxd
ArcGIS Map Document
GIS
.mxe
Macro Express Playable Macro
Executable
.mxf
Material Exchange Format File
Video
.mxfr
Mandelbrot Explorer Fractal Region File
Settings
.mxi
Adobe Extension Information File
Data
.mxl
Compressed MusicXML File
Audio
.mxml
Flex MXML Component
Developer
.mxp
Adobe Extension Package
Plugin
.mxt
ArcGIS Map Template
GIS
.myapp
Visual Studio Application XML File
Developer
.mycolors
Stardock MyColors Theme File
Settings
.myd
MySQL Database Data File
Database
.mydocs
Send To My Documents
System
.myi
MySQL MyISAM Index File
Data
.mys
Vineyard Captured Video File
Video
.mzp
MAXScript Zip Package
Compressed