Ext.
|
Description
|
Used by
|
M
|
Mathematica Package File
|
Mathematica
|
M
|
MATLAB M-File
|
MATLAB
|
M2
|
WoW Model Object file
|
Blizzard Entertainment games (World of Warcraft/Warcraft series)
|
M2TS
|
MPEG 2 Transport Stream
|
Various media playback devices / software
|
M3U
|
M3U playlist file
|
Winamp, XMMS
|
M3U8
|
Unicode version of M3U playlist file (UTF-8)
|
Winamp, XMMS
|
M4A
|
Advanced Audio Coding
|
|
M7P
|
Multilizer 2007 and 2009 localization project file
|
Multilizer
|
MAI
|
Mail
|
VAX
|
MAK
|
Makefile
|
|
MAK
|
Project file
|
VB - VC ++
|
MAN
|
User guide (manual)
|
|
MAP
|
Color palette file
|
|
MAP
|
Format data
|
Micrografx Picture Publisher
|
MAP
|
Linker map file
|
|
MAP
|
Map file (usually created by compilers)
|
|
MAP
|
Map
|
Atlas MapMaker
|
MAP
|
Network map
|
AccView
|
MAP
|
Game map for Duke Nukem 3D
|
|
MAR
|
Assembly program
|
VAX Macro
|
MAR
|
Microsoft ARchive
|
MSN Explorer (possibly other Microsoft products too)
|
MAR
|
Mozilla ARchive
|
Mozilla Updater (used to house binary updates to products)
|
MAS
|
SmartMaster set
|
Freelance Graphics
|
MAT
|
Data
|
MATLAB
|
MAT
|
Microsoft Access Table
|
Microsoft Access
|
MAX
|
MAX source code file
|
|
MB
|
Memo field values for database
|
Paradox
|
MBK
|
Multiple index file backup
|
dBASE IV
|
MBX
|
Mailbox data
|
Eudora/ZERBERUS
|
MCC
|
Configuration file
|
Mathcad
|
MCD
|
MathCad file
|
MathCad
|
MCF
|
Font file
|
Mathcad
|
MCF
|
Photo book or photo calendar layout file
|
FotoInsight Designer
|
MCF
|
Multimedia Container Format (predecessor of Matroska)
|
|
MCI
|
MCI command script
|
Media Control Interface
|
MCL
|
Multi Edit macro library
|
Multi Edit
|
MCL
|
Cartesian manipulator for laser systems
|
|
MCP
|
Application script
|
Capsule
|
MCP
|
Printer driver
|
Mathcad
|
MCW
|
Text file
|
MacWrite II
|
MDL
|
Quake 1 Model File
|
id Software
|
MD2
|
Quake 2 Model File
|
id Software
|
MD3
|
Quake 3 Model File
|
id Software
|
MD5
|
Doom 3 and Quake 4 Model File
|
id Software
|
MD
|
Archive
|
mdcd10.arc
|
MDA
|
Data
|
Microsoft Access
|
MDA
|
Microsoft Access system database
|
Microsoft Access
|
MDB
|
Microsoft DataBase
|
Microsoft Access
|
MDF
|
Several uses
|
|
MDL
|
Model
|
3D Design Plus or Simulink
|
MDL
|
Spreadsheet
|
CA-Compete!
|
MDM
|
Modem definition file
|
TELIX
|
MDMP
|
Mini dumpfile
|
|
MDR
|
Microdrive file
|
ZX Spectrum emulator by g.a.lunter
|
MDS
|
Midi Session
|
Sound Imp.
|
MDT
|
Data table
|
Microsoft ILink incremental linker
|
MDX
|
Multiple index file
|
dBASE IV
|
MDZ
|
Text description of music module
|
Cubic Player - Cross-View
|
ME
|
MultiEdit configuration
|
MultiEdit
|
ME
|
Text file READ.ME
|
|
MEB
|
Macro Editor bottom overflow file
|
WordPerfect Library
|
MEC
|
MECCA source
|
Maximus
|
MED
|
Macro Editor delete save
|
WordPerfect Library
|
MED
|
Music format
|
MED/OctaMED
|
MEM
|
Macro Editor macro
|
WordPerfect Library
|
MEM
|
Memory variable save file
|
dBASE IV - FoxPro - Clipper
|
MEM
|
Memos datafile
|
Clarion
|
MEM
|
Mnemosyne database
|
Mnemosyne; other spaced repetition software
|
MEQ
|
Macro Editor print queue file
|
WordPerfect Library
|
MER
|
Macro Editor resident area (vakioalue)
|
WordPerfect Library
|
MES
|
Macro Editor work space file
|
WordPerfect Library
|
MES
|
Message
|
|
MET
|
Document
|
Omnipage Pro
|
MET
|
Macro Editor top overflow file
|
WordPerfect Library
|
MET
|
OS/2 graphics metafile
|
PICVIEW.EXE
|
MEU
|
Menu group
|
DOS Shell
|
MEX
|
Macro Editor expound file
|
WordPerfect Library
|
MEX
|
MEX file (executable command)
|
Matlab
|
MF
|
Metafont file
|
TeX
|
MFA
|
Source code file
|
Multimedia Fusion 2 / The Games Factory 2
|
MFF
|
MIDI
|
Cakewalk, MTPro 4
|
MFM
|
Music format
|
DMP
|
MGF
|
Font
|
Micrografx
|
MGF
|
Materials and Geometry Format
|
|
MGX
|
Designer 4.1 Drawing
|
Designer 4.1
|
MHT
|
Web Archive Single File
|
|
MIB
|
Snmp MIB file
|
|
MID
|
Standard MIDI file
|
music synthetizers, Winamp
|
MIDI
|
See MID
|
|
MIFF
|
Magick Image File Format
|
|
MII
|
Datafile
|
MicroStat-II
|
MIME
|
Message in MIME format (RFC822)
|
|
MIO
|
MyInfo topic
|
Milenix MyInfo
|
MIS
|
Mission, used by many games
|
|
MIX
|
Object file
|
Power C
|
MK
|
Makefile
|
|
MK
|
Makefile
|
|
MK
|
Usually makefile
|
|
MKE
|
Makefile
|
Microsoft Windows SDK
|
MKG
|
Makefile
|
|
MKI
|
Graphics format (Japan MKI)
|
|
MKI
|
Japanese graphics MAKIchan format
|
MagView 0.5
|
MKS
|
Data
|
TACT
|
MKV
|
Matroska Multimedia Container
|
Media Player Classic, Windows Media Player, Matroska Splitter
|
ML3
|
Project
|
Milestones 3.x
|
MLB
|
Macro library file
|
RT-11, Symphony
|
MLI
|
3DS Materials Libraries
|
3D Studio
|
MLRAW
|
Data
|
Moonlight Creator RAW format 3D object
|
MLV
|
LabVIEW MathScript
|
|
MM
|
Text file
|
MultiMate Advantage II, FreeMind mind map file (XML)
|
MMF
|
Mail message file
|
Microsoft Mail
|
MMM
|
Multimedia movie file, RIFF RMMP format
|
MacroMind Director 3.x
|
MMO
|
Memo writer file
|
RapidFile
|
MMP
|
Output video format from Bravado board
|
|
MN
|
MuPAD Pro Notebook
|
Workspace file of MuPAD (integrated in Matlab)
|
MND
|
Menu source
|
AutoCAD Menu Compiler
|
MNG
|
Map
|
DeLorme Map'n'Go
|
MNT
|
Additional (FPT) menu description file
|
FoxPro
|
MNT
|
Menu memo
|
FoxPro
|
MNU
|
Advanced macro file
|
HP NewWave
|
MNU
|
Menu
|
AutoCAD Menu Compiler - Norton Commander - Signature
|
MNU
|
Microsoft Mouse menu (for DOS apps)
|
|
MNX
|
Compiled menu file
|
AutoCAD
|
MNX
|
Main (DBF) menu description file
|
FoxPro
|
MNY
|
Account book
|
Microsoft Money
|
MO?
|
Packed mail
|
FTN software
|
MOB
|
Device definition file
|
PEN Windows
|
MOBI
|
eBook
|
Mobipocket
|
MOD
|
Modula language source
|
|
MOD
|
MODULA-2 source code file
|
Clarion Modula-2
|
MOD
|
Module—used by Windows for DLL which implement DOS support
|
Win
|
MOD
|
Music format (Amiga module)
|
DMP - ST - MDP - VP
|
MOL
|
MOD4WIN PlayList
|
Mod4Win
|
MOL
|
MDL Molfile
|
RasMol
|
MOL2
|
Tripos’ Sybyl MOL2 Format
|
SYBYL, RasMol
|
MON
|
SYSGEN monitor build procedure
|
RT-11
|
MON
|
Monitor description
|
ReadMail
|
MOP
|
MOPAC input file
|
MOPAC, RasMol
|
MOV
|
Animation format (Mac)
|
QuickTime
|
MOV
|
Movie file
|
AutoCAD AutoFlix
|
MP2
|
Mpeg audio file
|
Winamp, xing
|
MP3
|
MPEG audio stream, layer 3
|
AWAVE, CoolEdit(+PlugIn), Winamp, many others
|
MP4
|
multimedia container format, MPEG 4 Part 14
|
Winamp
|
MPA
|
MPEG audio stream, layer 1,2,3
|
AWAVE
|
MPC
|
Calendar file
|
Microsoft Project
|
MPC
|
Musepack audio
|
|
MPEG
|
multimedia containter format, video, audio
|
MPEG Player, Winamp
|
MPG
|
see MPEG
|
|
MPKG
|
Multipackage installer script
|
Mac OS X
|
MPL
|
MediaRack Midi Playlist
|
MediaRack
|
MPM
|
MathPlan macro
|
WordPerfect Library
|
MPP
|
Project file
|
Microsoft Project
|
MPPZ
|
MagicPlot project file
|
MagicPlot
|
MPQ
|
Mo'PaQ Archive
|
Blizzard games
|
MPR
|
Generated executable menu file
|
FoxPro
|
MPR
|
Multilizer 5.x and 6.x localization project file
|
Multilizer
|
MPR
|
Command & Conquer: Red Alert 2 map file
|
Red Alert 2
|
MPT
|
Bitmap graphics (Multipage TIFF)
|
|
MPV
|
View file
|
Microsoft Project
|
MPX
|
Compiled executable menu file
|
FoxPro
|
MPX
|
Video format
|
|
MPZ
|
Miradi Project Zipfile
|
Miradi
|
MRB
|
Multiple Resolution Bitmap graphics file
|
Microsoft C/C++
|
MRC
|
mIRC file
|
mIRC
|
MRK
|
Windows User Benchmark
|
Win95
|
MRS
|
Macro Resource file
|
WordPerfect for Win
|
MS
|
Microsoft antivirus report
|
MSAV
|
MSC
|
Microsoft C makefile
|
|
MSC
|
management saved console[2]
|
Microsoft; Microsoft MMC[3]
|
MSI
|
Windows Installer Package
|
Windows Operating Systems
|
MSDL
|
Manchester Scene Description Language
|
|
MSG
|
Message base (e.g. HMB)
|
|
MSG
|
Message text file (ASCII)
|
Microsoft Outlook
|
MSG
|
ZVoice digitized voice file
|
|
MSE
|
Set file
|
Magic Set Editor
|
MSO
|
Microsoft Word OLE Web Page Storage Stream
|
Microsoft Office
|
MSO
|
Microsoft Outlook metadata for a Microsoft Word 2000 email attachment.[4]
|
Microsoft Outlook
|
MSP
|
Bitmap graphics file
|
Microsoft Paint
|
MSP
|
Graphics format
|
Microsoft Paint
|
MSPRODUCER
|
Media Project
|
Microsoft Producer (for Microsoft PowerPoint XP/2003) Project
|
MSQM
|
data
|
Microsoft Message Queuing
|
MSN
|
Project
|
National Instruments for NI MultiSim-Electronic Circuit simulator
|
MSS
|
Manuscript text file
|
Perfect Writer - Scribble - MINCE - Jove
|
MST
|
Document
|
MS Test
|
MST
|
Minispecification file
|
Prosa
|
MST
|
Setup script file
|
Microsoft Windows SDK
|
MSW
|
Text file
|
Microsoft Word
|
MSX
|
CP/M archive
|
MSX
|
MTH
|
Math file
|
Derive
|
MTL
|
Wavefront
|
|
MTM
|
Music format
|
MultiTracker
|
MTS
|
Master Track Pro Files
|
MTPro 4
|
MTS
|
data
|
F1 2001, F1 2002 and F1 Challenge 1999 - 2002 car physics (All from the EA Sports F1 Series)
|
MTV
|
MTV Ray Tracer graphic file
|
|
MTW
|
Datafile
|
Minitab
|
MU
|
Quattro pro for DOS Menu definition file
|
Quattro Pro
|
MUS
|
Finale music document.
|
Finale
|
MUS
|
Music format (MIDI in Doom)
|
|
MUS
|
Sound file
|
MusicTime
|
MUZ
|
Hover Game MIDI File
|
Windows' Hover! Game[5]
|
MVF
|
Stop frame file
|
AutoCAD AutoFlix
|
MVI
|
Movie command file
|
AutoCAD AutoFlix
|
MVO
|
Data
|
Mad Virgin 3D object
|
MVW
|
Log file
|
Saber LAN
|
MWF
|
Animation
|
ProMotion
|
MWS
|
MWave DSP synths instrument
|
AWAVE
|
MXF
|
Material exchange format (RFC 4539, SMPTE 377M)
|
|
MXL
|
PackRat 5.0 support DLLs
|
PackRat 5.0
|
MXM
|
Material
|
Maxwell Render
|
MXP
|
Adobe Extension File
|
Adobe Dreamweaver and Adobe Flash
|
MXP
|
3ds Max Configuration File
|
3ds Max
|
MXP
|
MasterCook exported recipe
|
|
MXT
|
Data
|
Microsoft C
|
MYP
|
Presentation
|
MM Make Your Point
|
MZ
|
Binary-format Map
|
MazeEdit
|
MZE
|
Text-format Map
|
MazeEdit
|
MZG
|
Binary-format Map Collection
|
MazeEdit
|
MZX
|
Binary-format Encrypted Map
|
MazeEdit
|
Ext.
|
Description
|
Used by
|
NAM
|
Name Space Modules
|
Novell NetWare
|
NAP
|
Naplps file (VideoShow)
|
EnerGraphics
|
NAPLPS
|
North American Presentation Layer Protocol Syntax
|
|
NB
|
Text file
|
Nota Bene
|
NB
|
Wolfram Mathematica Notebook
|
Mathematica
|
NBF
|
Nokia Backup File
|
Nokia Mobile Phones
|
NC
|
Binary Data
|
netCDF software package
|
NC
|
Instructions for NC (Numerical Control) machine
|
CAMS
|
NC
|
Non-error checking preprosessed Goc source code
|
Geoworks
|
NCC
|
CNC (Computer Numeric Control) control file
|
CamView 3D
|
NCD
|
Norton Change Directory support file
|
Norton Commander
|
NCP
|
Re-volt Collision file
|
Re-volt
|
NDB
|
Network database
|
Intellicom - Compex
|
NDS
|
Nintendo DS ROM file used for Homebrew and commercial (Game) files on DS
|
|
NDL
|
Nodelist file
|
|
NDX
|
Index file
|
dBASE II - III - IV - dBFast
|
NEO
|
Raster graphics file
|
Atari Neochrome
|
NES
|
iNES ROM image format
|
|
NET
|
Network configuration/info file
|
|
NEU
|
Pro/Engineer neutral file format
|
PTC Pro/Engineer
|
netCDF
|
Network Common Data Format
|
|
NEW
|
New info
|
|
NFF
|
Haines Neutral File Format
|
|
NFF
|
WorldToolKit Neutral File Format
|
|
NFO
|
Folioview database
|
|
NFO
|
Help format
|
Nextpage Folio
|
NFO
|
Info file
|
Compact NFO Viewer
|
NG
|
Hypertext Database
|
Norton Guide
|
NGO
|
NG linker object file
|
NGML
|
NGS
;
|
NG compiler source file
|
NGC
|
NIF
|
netimmerse/gamebyro file
|
|
NIL
|
NIL
|
Icon Hear-It
|
NITF
|
National Imagery Transmission Format
|
|
NK2
|
e-mail address autocomplete archive
|
Microsoft Office Outlook
|
NL
|
Norton Desktop Icon Library
|
|
NLM
|
Netware loadable module
|
Novell Netware
|
NLS
|
National Language Support file
|
MS-DOS
|
NLX
|
Form
|
FormWorx 3.0
|
nmf
|
Node Map File
|
Used by SpicyNodes
|
nnn
|
Arj archive volumes up to 999
|
ARJ
|
nnn
|
Netware unicode rule table (e.g. 1250_Uni.036)
|
Novell Netware
|
nnn
|
News about smth with ext. of ver. number
|
|
nnn
|
RAR archive volumes up to 999
|
RAR
|
NOT
|
Notation
|
|
NOT
|
Yard Notes File
|
FYM
|
NP
|
Project schedule (Nokia Planner)
|
Nokia Planner
|
NPI
|
Source for DGEN.EXE interpreter
|
dBASE Application Generator
|
NPJ
|
Nile Project
|
Game Mission Editor
|
NRG
|
Nero Disc Image File
|
Nero Express / Burning ROM
|
NRW
|
Nikon Coolpix RAW image
|
Nikon
|
NSA
|
media
|
Nullsoft Streaming Audio
|
NSF
|
database
|
Lotus Notes
|
NSF
|
Music module
|
NES Sound File
|
NSS
|
Norton screensaver module
|
NC - NDW Screen Saver
|
NST
|
Music module
|
Amiga Noise Tracker
|
NSV
|
media
|
Nullsoft Streaming Video
|
NSX
|
Compound index file
|
SuccessWare SIX 3.00
|
NT
|
Startup files
|
Windows NT
|
NTF
|
database design template
|
Lotus Notes
|
NTH
|
Nokia Theme File
|
Nokia PC Suite
|
NTR
|
Executable ASCII text file (strip header and rename)
|
netrun31.zip
|
NTS
|
Executable ASCII text file (strip header and rename)
|
netsend1.zip
|
NTS
|
Tutorial
|
Norton
|
NTX
|
Database index file
|
Clipper 5
|
NUF
|
Message for new users on their 1st call
|
Procomm Plus
|
NUMBERS
|
Numbers spreadsheet file
|
Numbers (Apple iWork '08)
|
NV
|
NewViews DOS accounting database
|
QW Page NewViews
|
NV2
|
NewViews accounting database
|
QW Page NewViews
|
NWS
|
Info text file (latest news) (ASCII)
|
|
NXT
|
Sound (NeXT format)
|
|
Ext.
|
Description
|
Used by
|
O$$
|
Outfile
|
Sprint
|
O
|
Object file
|
UNIX - Atari - GCC
|
O01
|
Typhoon vOice file
|
AWAVE
|
OAZ
|
Fax
|
NetFax Manager
|
OB
|
Object cut/paste file
|
IBM LinkWay
|
OBD
|
Microsoft Office Binder
|
MSOffice
|
OBJ
|
Compiled machine language code
|
|
OBJ
|
Object code
|
Intel Relocatable Object Module
|
OBJ
|
Wavefront Object
|
|
OBJF
|
Data
|
Triangle strips object
|
OBR
|
Object browser data file
|
Borland C++
|
OBS
|
Script
|
ObjectScript
|
OBT
|
Microsoft Office Binder Template
|
MSOffice
|
OBV
|
Visual interface
|
ObjectScript
|
OBZ
|
Microsoft Office Binder Wizard
|
MSOffice
|
OCF
|
Object Craft File
|
Object Craft
|
OCD
|
OCAD Map File
|
OCAD
|
OCR
|
Incoming fax transcribed to text
|
FAXGrapper
|
OCT
|
Musical file
|
Pctalizer
|
OCX
|
New Custom Control's format in VB 4.0
|
Visual Basic
|
OCX
|
OLE custom control
|
|
ODB
|
OpenDocument database
|
OpenOffice.org Base
|
ODF
|
OpenDocument formula
|
OpenOffice.org Math
|
ODG
|
OpenDocument drawing
|
OpenOffice.org Draw
|
ODIF
|
Open Document Interchange Format
|
|
ODL
|
Object Description Language
|
|
ODL
|
Type library source
|
Visual C++
|
ODM
|
OpenDocument master document
|
OpenOffice.org Writer
|
ODP
|
OpenDocument presentation
|
OpenOffice.org Impress
|
ODS
|
OpenDocument spreadsheet
|
OpenOffice.org Calc
|
ODT
|
OpenDocument text document
|
OpenOffice.org Writer
|
OFD
|
Form definition
|
ObjectView
|
OFF
|
Object File Format vector graphics file
|
|
OFF
|
Object File Format vector graphics
|
|
OFM
|
PostScript font description file
|
|
OFN
|
Microsoft Office documents
|
Microsoft Office
|
OGG
|
Ogg multimedia container format
|
|
OHB
|
Source
|
On Hand Basic
|
OHS
|
Outbound History
|
Bink/+
|
OIF
|
QuickBase file format
|
|
OKT
|
Music (8 channels)
|
Oktalyzer
|
OKT
|
Music format
|
Oktalyzer
|
OLB
|
Object library
|
VAX
|
OLD
|
Backup file
|
|
OLI
|
Text file
|
Olivetti
|
OLSR
|
Configuration file
|
olsrd
|
OMA
|
Audio file
|
Labelgate CD 2, MAGIQLIP2
|
OOF
|
Data
|
Outrage 3D Object Format (Descent)
|
OOG
|
Data
|
WEBOOGL 3D object
|
OOM
|
Swap file
|
Shroom
|
OPJ
|
Origin Project File
|
Origin version 4.1 and later
|
OPN
|
Active options
|
Exact
|
OPT
|
Options
|
name used by many programs for configuration information
|
OPT
|
Delphi project options
|
Borland Delphi
|
OPT
|
Optimize support file
|
QEMM
|
OPW
|
Organization chart
|
Org Plus for Windows
|
OPX
|
Inactive options
|
Exact
|
ORA
|
Parameter file
|
Oracle
|
ORC
|
Orchestra MIDI file
|
CSound
|
ORG
|
Calendar file
|
Lotus Organizer
|
ORG
|
Older Origin Project
|
Origin versions 4 or earlier
|
OTG
|
OpenDocument drawing template
|
OpenOffice.org Draw
|
OTB
|
Over-the-air bitmap graphics
|
|
OTF
|
Subtitle font information for media content
|
Media players / software which support PGS subtitling
|
OTH
|
OpenDocument HTML document template
|
OpenOffice.org
|
OTL
|
Outline font description
|
Z-Soft Type Foundry
|
OTL
|
Ventura Publisher's Type Foundry Outline Editor format
|
|
OTP
|
OpenDocument presentation template
|
OpenOffice.org Impress
|
OTS
|
OpenDocument spreadsheet template
|
OpenOffice.org Math
|
OTT
|
OpenDocument text document template
|
OpenOffice.org Writer
|
OTX
|
Text file
|
Olivetti Olitext Plus
|
OUT
|
Output file
|
|
OV1
|
Overlay file (part of program to be loaded when needed)
|
|
OV2
|
Overlay file (part of program to be loaded when needed)
|
TomTom Point of Interest
|
OVD
|
Datafile
|
ObjectVision
|
OVL
|
Overlay file (part of program to be loaded when needed)
|
|
OVR
|
Overlay file (part of program to be loaded when needed)
|
|
OXT
|
OpenOffice.org extension
|
OpenOffice.org
|
