.??_ Files ending in "_" are often compressed install files of the same
name (e.g., .EX_ expands to .EXE, .DL_ expands to .DLL, etc.)
.M Matlab Function
Brief Macro Source
Mathematica File
Limbo Interface Declaration (Inferno OS)
Cliq Accessories Datebook Modification File [Linux Suite PDF Description]
Desktop Color Separation Specification Magenta Layer (usually an EPS file)
.M_U MazeGold Critical File Backup
.M?? Ingres Modify Table/Index File (?? = Hex 00 to FF)
.M$S MindStor Firmware Update File (M$A$W.M$S)
.M11 MASS11 Text File
.M12 Proprietary Data Format for Interchange of Defense Form Data with Mil-Pac Technology Software Products (link is PDF file)
S-BASIC File
Hydrographs Synthesis Project File
SHARP MZ-series Emulator File
.M15 Apple MPEG-1 Video
.M18 Accolade Golf Course File
.M1A Apple MPEG-1/2 Audio
.M1V MPEG-1 Video File
.M2A Apple MPEG-1/2 Audio
.M2P MPEG-2 Program Stream Format File
.M2S MPEG-2 Audio and Video (system stream)
.M2V MPEG-2 Video Only File
.M3 Modula 3 Program File
.M32 Dr.T MIDI File
.M3A MPEG Archive Enhanced .M3U Playlist File
.M3D 3D Animations Macro
Corel Motion 3D Animation
EverQuest File
.M3S Myst III Exile Saved Game
.M3U MP3 Playlist File [WinAmp] [MattBatt iAM-player]
.M4 UNIX M4 Preprocessor File
.M75 Apple MPEG-1 Video
.M8 Heretic II MipMap [XnView]
.MA Maya File (ASCII)
Diablo II Map File
.MA3 Harvard Macro (Harvard Graphics taken over by Serif)
.MAC MacPaint Bitmap Graphic [XnView]
Macro (various)
.MACP MacPaint Bitmap Graphic [XnView]
.MAD MS Access Module Shortcut [Buy Office XP at Shop.Microsoft]
Game Movie File (unverified)
.MAF MS Access Form Shortcut [Buy Office XP at Shop.Microsoft]
.MAG MPS Magro Paint System Graphic
MS Access Diagram Shortcut [Buy Office XP at Shop.Microsoft]
MAGIchan Graphic [XnView]
.MAI VAX Mail
.MAK Make File (compiler project file)
.MAM MS Access Macro Shortcut [Buy Office XP at Shop.Microsoft]
.MAN Manual (often an ASCII text file)
Windows 2000 Mandatory User Profile (C:/DOCUMENTS AND SETTINGS/USERNAME/NTUSER.MAN)
.MANIFEST MS Visual Stylesheet for Windows Forms (Text file)
.MAP Image
Server-side Image Map (allows one to map link locations in a Web graphic)
Color Palette
AccView Network Map
Atlas MapMaker Map
DIV Game Studio Map [XnView]
Fenix Map [XnView]
Ingres Termcap Mapping File
Poser 3D Map File
WorldCraft Quake/Half-Life Game Level File
Blood Game File Map
Duke Nukem Game Level Data File
...and many more games (too many to list)
Linker Map
Micrografx Picture Publisher Format Data
PROGNOSIS Map Document File
.MAPIMAIL MS Outlook Express Mail File
.MAQ MS Access Query Shortcut [Buy Office XP at Shop.Microsoft]
.MAR MS Access Report Shortcut [Buy Office XP at Shop.Microsoft]
VAX Macro Assembly Program
Bibliographic Data Format (usually .MRC)
.MAS Focus Master Data Definition
MS Access Stored Procedures [Buy Office XP at Shop.Microsoft]
Lotus Freelance Graphics Smartmaster File
QuickCard File
.MAT Sound File
Pro/Engineer Material Properties File
Matlab Variables Binary File
MS Access Table Shortcut [Buy Office XP at Shop.Microsoft]
Autodesk 3D Studio Max and Viz File
Poser 3D Pose File
.MAUD Sound File [Linux Player]
.MAV MS Access View Shortcut [Buy Office XP at Shop.Microsoft]
.MAW MS Access Data Access Page
.MAX Kinetix's 3D Studio MAX Scene
Autodesk 3ds Max Scene File
Maximizer Contact & E-business Program
Paperport Scanned Image [Viewer]
Max Source Code
OrCAD Layout File
.MAZ Hover Maze Data
Division's dVS/dVISE File
.MB Paradox Memo Holder
Maya Binary (3D Software Maya Scenes)
.MB1 Apogee Monster Bash Data File
.MBD Multimedia Builder MP3 Authoring File
.MBF MS Money Backup File
.MBFS Stardent AVS X Image [XnView]
.MBFAVS Stardent AVS X Image [XnView]
.MBG Mailbag Assistant E-mail Archive
.MBK dBase IV Multiple Index Backup
VersaPro Motion Block Backup
.MBM SymbianOS Multi BitMap Image (native EPOC image format) [XnView]
.MBS Mailbag Assistant Script
.MBT ecBuilder Template (Web site cataloging)
.MBW MarketBrowser (investment charting/analysis)
.MBX Mailbox Message File (Outlook v1-4 or Eudora and others)
.MC MetaCard Script
PlaySaver and PSEmuPro Memory Card Save and Single Game Save
.MC8 Mastercam 8 File
.MCA i-deas Web ACCESS File
.MCC Mathcad Configuration
Mylar City Character Editor
Dialer10 Calling Card
Monu-Cad Pro CAD File
VectorWorks/MiniCAD File [Viewer]
Incite Media Assistant File
.MCD Mathcad Document
Craig McDowall.com NotePad
Monu-Cad Pro CAD File
Bleem! Memory Card Save
.MCF Mathcad Font
Meta Content Format File (describes a Web site) [Process description]
Master Command File
TMPGEnc Template (Multimedia Container Format File)
.MCH Macromedia Xtra Cache File
.MCI Media Control Interface Command Set
.MCL Multimedia Manager Collection File
Macro Command Language (Symbol handheld terminals)
.MCP Mathcad Printer Driver
Capsule Application Script
.MCQ McAfee Quarantined File
.MCR DataCAD Keyboard Macro File
PlaySaver and PSEmuPro Memory Card Save and Single Game Save
CuteFTP Script
.MCS MathCAD Format File
.MCT Musicator
.MCW MacWrite II Macintosh Text File
.MCX Graphic File
.MD Compressed Archive File
Teknical eLearning Objects Meta-Data File (stores info on related file)
.MD1 Gear CD Suite File
.MD5 MD5summer (generates and verifies md5 checksums) [MD5 Generator] [fsum Checksum Utility]
.MDA MS Access Add-in
MS Access 2 Workgroup
.MDB MS Access Database
MS Access Application
Mediator Multimedia Data
.MDE MS Access Database File
.MDF Menu Definition File
MS-SQL Master Database File
Accelio Capture Classic (JetForm) Filler (JetForm Corp became Accelio 12 Sep 2001)
I-deas Master Drafting Machine Data File
.MDL Digitrakker Music Module (by n-FaCToR)
Rational Rose
Quake Model File
3D Design Plus Model
Simulink Simulation Model
ASTi Model Builder File
CA-Compete! Spreadsheet
Half-life Model [XnView]
Moray Model (wireframe modeller supporting POV-Ray 3.1)
Symbian OS MIME Type Library
.MDM Telix Modem Definition
.MDMP WinXP Trouble Report (extension is added to file sent)
.MDN MS Access Blank Database Template [Buy Office XP at Shop.Microsoft]
.MDO MS Internet Information Server Configuration Backup
.MDP MS Developer Studio Project
.MDR FaxTalk Modem Doctor Modem Report File
.MDS Media Description File [Fantom CD Emulator]
.MDT MS Access Add-in Data [Buy Office XP at Shop.Microsoft]
MS ILink Incremental Linker Data Table
.MDW MS Access Workgroup Information [Buy Office XP at Shop.Microsoft]
.MDX dBase IV Multiple Index [File Structure]
Avery Label Pro Re-Index File
.MDZ MS Access Wizard Template [Buy Office XP at Shop.Microsoft]
.ME Information (e.g., READ.ME)
.MEA Meazure File (screen measurement and capture utility)
.MEB WordPerfect Macro Editor Bottom Overflow File
.MED WordPerfect Macro Editor Delete Save
OctaMED Tracker Module
.MEL Ericsson Phone Melody
Maya Embedded Language Script
.MEM WordPerfect Macro Editor Macro
Memory File of Variables
MS FoxPro Memory Variable Save File
.MEN Menu
.MEQ WordPerfect Macro Editor Print Queue
.MER WordPerfect Macro Editor Resident Area
Data Interchange Format
.MES Message File
WordPerfect Macro Editor Work Space
.MET WordPerfect Macro Editor Top Overflow File
Presentation Manager Meta File
OmniPage Document
eDonkey2000 File
.METHODS Likely a text file (e.g., README.METHODS)
.MEU DOS Shell Menus
.MEX Matlab Executable Command
WordPerfect Macro Editor Expound File
mexReader Multimedia File
.MEZ RealArcade Game Information
.MF MetaFont Text File
.MFA MS Site Server 3.0 Report Definition
.MFF MIDI File Format
.MFG MediaForge Runtime Player
.MFM VTeX Multiple Master Font Metrics (a variant of the Adobe Font Metrics (AFM) format?)
.MGC MGCSoft Equation Editor File
.MGCF MagicInstall Compressed File
.MGD Master Grade Gradebook
.MGF Image File
Micrografx Font
Materials and Geometry Format File
.MGL MosASCII Graphics Library
.MGM MGCSoft Equation Editor Macro File
.MGR MGR Bitmap [XnView]
.MGX Micrografx Picture Publisher Clipart
.MGZ Metal Gear Solid Archive [Dragon UnPACKer]
.MH Graphic File
.MHG Multimedia File
.MHK Riven Movie Data File (Mohawk Archive)
.MHP MS Home Publishing Project
.MHT MS MHTML Document (Archived Web Page)
.MHTML MS MHTML Document (Archived Web Page)
.MI Miscellaneous
CoCreate CAD File
.MIB Management Information Base File (SNMP Management Programs)
.MIC MS Image Composer File
.MID MIDI File [IrfanView]
.MIDI MIDI File [IrfanView]
.MIF MIDI Instrument
Adobe FrameMaker Interchange Format
Software License Tracking Tool (CERTAUTH.MIF)
MapInfo Interchange Format File
MicroHof .MIF Assembler File
Image Magick File [XnView]
.MIFF Image Magick File [XnView]
.MII MicroStat II Data File
.MIL Group 4 Fax File
Micro Illustrator Uncompressed Graphic [XnView]
.MIM Multi-Purpose Internet Mail Extensions (MIME) File [MIME]
.MIO mexReader Multimedia File
.MIP Paint Shop Pro Multiple Image Print File
.MIS Delta Force Land Warrior Mission [Fan site]
Tribes 2 Game File
MagicInstall Installation Script (Under development Feb 2002)
.MIX Power C Object File
Multilayer Picture File (MS PhotoDraw 2000 & MS Picture It!)
Don Knuth's MIX Emulator
Command & Conquer Movie/Sound File
Techno eJay Music Mix File
OzWin CompuServe E-mail/Forum Access Index File
.MJ MovieJack DVD Ripper File
.MK Make File
.MKD Malz++Kassner CAD5 Drawing
.MKE Make File
.MKI Picture File
.MKL Malz++Kassner CAD5 Drawing Library
Créatoria
.MKS Tact Data
.ML3 Milestones 3.x Project
.ML6 PowerPoint Milestone File
.MLB Macro Library
.MLD Multilizer Dictionary
.MLI Encyclopedia Media List
3D Studio's Material-Library File
.MLK Sierra Mastercook File
.MLM Novel Groupwise E-mail File
.MLS Miles Sound Tools Compressed DLS
.MM Macro Mania Macro
Multimate Advantage File
Lightscape Material Map
.MMB MultiMedia Builder
Oracle Forms Menu Binary Source Code
.MMC Media Catalog
MSoffice Media Content (MS OfficeXP)
.MME Multi-Purpose Internet Mail Extensions (MIME) File [MIME]
.MMF Meal Master Format
MS Mail File
.MMI Memo Open Client
.MML Mail Meta Language
.MMM Animation MS Multimedia Movie
MacroMind Directory RIFF/RMMP Format Movie
.MMO RapidFile Memo Writer
.MMP MindManager Map File
Gammadyne Mailer Project File
Bravado Board Video Output Format
.MMPBT MindManager Branch Template File
.MMPT MindManager Template
.MMS Miles Sound Tools (Midi+DLS/MLS)
.MMSCRIPT MindManager Script File
.MMT Nimbus 7 SAMS Data File (monthly mean retrieved temperatures)
.MMV Sony MovieShaker File
.MMW Microsoft Media Content
.MMX Command & Conquer Red Alert 2 Map File
Oracle Forms Compiled Menu
.MMZ MusicMatch Theme File
.MN2 Descent2 Mission File
.MN3 Descent3 Mission File
.MN4 Microsoft Money Database (older version)
.MNB MuPAD File
.MNC My Notes Center File
.MND AutoCAD Menu Program File
MNI Mandelbrot for Windows
.MNG Animation Shop Animation
DeLorme Map'n'Go Map
Multi-image Network Graphic [XnView]
.MNO Monopoly Saved Game
Macromedia Design Notes
.MNR AutoCAD Compiled Menu File
.MNS AutoCAD ASCII Menu File
.MNT Foxpro Menu Memo
.MNU Menu File (various)
HP NewWave Advanced Macro
.MNW Menu File (various)
.MNX AutoCAD Compiled Menu File
Foxpro Menu
.MNY MS Money File
.MOB Device Definitions
.MOD Music File (various)
Model File (various)
Modula-2 Program File
ProModel Optimization Software Suite Model
Windows Kernel Module
Amiga and PC Tracker Module
MS Multiplan Spreadsheet
Monarch File (data mining)
.MODEL Catia File
.MOL MDL Molfile (MIME type chemical/x-mdl-molfile) [Requires Chime Plug-in]
Easy Palette Object Library
.MON ReadMail Monitor (UNIX)
.MOP Mopac Input File (MIME type chemical/x-mopac-input)
.MOR Poser 3D Morph Target File
.MOV QuickTime Video Clip [IrfanView]
Apple QuickTime Audio
AutoCAD AutoFlix Movie
.MOVERADDIN Mover (Inventory Management) Add-in
.MOVERBACKUP Mover (Inventory Management) Backup Set
.MOVERCONFIG Mover (Inventory Management) Configuration
.MOVERDB Mover (Inventory Management) Database
.MOVERREG Mover (Inventory Management) Registration Info
.MOVERTEMPLATE Mover (Inventory Management) Template
.MOVIE Video
.MOX Extend Simulation Model File
.MOZ Netscape Temp File
.MP Multiplan File
Maya Personal Learning Edition File
EARS Component File (EARS = UK Liberal Democrats Election Agents Record System) [Filename starts with E]
.MP+ MpegPlus Audio File (replaced by .MPC)
.MP1 MPEG Audio Stream, Layer I
.MP2 MPEG Audio Stream, Layer II
.MP2V MPEG Audio Stream, Layer II
.MP3 MPEG Audio Stream, Layer III [IrfanView]
SHARP MZ-series Emulator File
.MP4 iVAST MPEG-4 (hold BIFS-Binary Information For Scene representation) [MPEG-4 Industry Forum]
.MPA MPEG Audio Stream, Layer I, II or III
Palm Memo File
.MPC MS Project Calender
MP3 Collector Collection Manager File
VersaPro Compiled Motion Block
Musepack Audio File (new format replacing .MP+)
.MPD Mini Port Driver
MS Project Database File
.MPDEX MPdex MP3 Database Utility
.MPE MPEG Movie Clip
.MPE.EXE MP3 Digital Player Wrapper
.MPEG MPEG Movie
.MPF MS Design Gallery
MosASCII Project Workspace File
.MPG MPEG Animation [IrfanView]
MPEG 1 System Stream
.MPGA Mpeg-1 Layer3 Audio Stream
.MPH MS Publisher
.MPJ RoboHTML Project
Mountain Video Editing File (Atari)
.MPK Augmented MS-Project File
.MPM WordPerfect MathPlan Macro
Max Payne MOD Archive [Added Info]
.MPNT MacPaint Bitmap File [XnView]
.MPO Augmented MS-Project File
.MPP MS Project File
CAD Drawing File
.MPQ Blizzard Game Data File
(also other games)
.MPR Foxpro Program
Westwood Studios Game File (e.g., Red Alert, et.al. - should be a text file)
FileMaker Spelling Dictionary
.MPS Multimedia File
MPEG-1 Audio and Video File (system stream)
Casio PDL Pocket Streets Map (Microsoft product - see just below)
MS Pocket Streets Map File
Max Payne Saved Game
Garmin Mapsource GPS Mapping Interface
MySweetNix! (change MSN Messenger Service nickname every n seconds)
.MPT MS Project Template File
Multipage TIFF Bitmap
.MPV MS Project View
MPEG-1 Video File
.MPV2 MPEG Audio Stream, Layer II
.MPW MosASCII Project Workspace File
.MPX Foxpro Compiler Menu
MS Project Export File
RCA/Lyra Handheld MP3 Player File (secure MP3 format that only plays in this player)
.MRB MS C++ Multiple Resolution Bitmap Graphic
.MRC MIRC Script File
Bibliographic Data Format
.MRF Marks Russel File [XnView]
.MRI MRI Scan
.MRK Informative Graphics Markup File
.MRO SharpEye Music Reader File
.MRS WordPerfect Macro Resource File
.MRW Minolta Diamage RAW Graphic (use view software supplied with camera)
.MS Checksum File for Anti-Virus
.MS1 OzWin CompuServe E-mail/Forum Access Message File
.MS3D MilkShape 3D Model
.MSA Magic Shadow Archive
.MSC Microsoft Common Console Document
MS C Makefile
.MSF Multiple Sequence File (biomedical analysis)
.MSG Program Message
OzWin CompuServe E-mail/Forum Access Message File
MS Mail Message
.MSH MASH (The Microsoft Agent Scripting Helper)
.MSI Windows Installer File (associates components with features and contains installation control info)
.MSK Autodesk Mask File
PaintShop Pro Mask File [XnView]
.MSM MultiSIM Circuit Diagram
.MSN MS Network Document (possibly nicknames)
Descent Mission File
.MSO MS Word OLE Web Page Storage Stream [Buy Office XP at Shop.Microsoft]
MS FrontPage File [Buy Office XP at Shop.Microsoft]
Math Script Object File
.MSP MS Paint Graphic File [XnView]
Windows Installer Patch
Magix Music Studio File
.MSPX Related to Microsoft's .NET (still researching)
.MSR OzWin CompuServe E-mail/Forum Access SYSOP File
.MSRCINCIDENT MS Remote Assistance Request
.MSS Manuscript Text File (various)
Game Score
.MSSYTLES Windows Visual Style File
.MST Minispecification
DATAIR Pension System Master File
Windows SDK Setup Transform Script (contains mods to apply to package during installation)
ChemFinder Chemical Structure Index
Visual Test Source File
.MSW Word Text File [Buy Office XP at Shop.Microsoft]
.MSWMM Microsoft Windows Movie Maker Project (Part of WinME & XP)
.MSV Sony Memory Stick Format
.MSW MS Word Text File
.MSX Compressed CP/M File Archive
.MTA MS Flight Simulator Maintenance File
.MTB MINITAB Exec File (a macro file)
.MTD Digital Sheet Music [Viewer]
.MTF Darkstone Archive [Dragon UnPACKer]
MicroSurfer File (Link manager/accelerator)
.MTH Derive Math File
.MTK Matrikon Software License File
.MTL MathLook File
.MTM Sound File
MultiTracker Music Module
.MTP L&H Power Translator Pro
.MTV MTV Ray-tracer [XnView]
.MTW Minitab Data File
.MTX Temporary File often used by a browser or TWAIN device
.MU Quattro Menu
.MUC Music Collector Collection Manager File
.MUF ProtoMuck Multi User Forth Program
.MUL Ultima Online Game
.MUP Music Publisher File
.MUS MusicTime Audio File
Finale Music Score
Harmony Assistant, Melody Assistant, Myriad Music plug-in, Melody Player
.MV Miva Script
.MV3 Oozic 3D MusicVideo
.MVA Matrox Video Card Driver
.MVB Database
MS Multimedia Viewer File [Viewer Download]
Note: The viewer download is old. Don't overwrite any new files with old.
.MVC Music Collector Collection Manager File
.MVD MicroDVD DVD Movie
.MVE Interplay Video File [Descent2]
.MVF Movie Stop Frame File
.MVI AutoCAD Movie Command File
.MVW Saber LAN Log File
.MW4 MechWarrior 4 Map
.MWD Photo Soap2 File
.MWF ProMotion Animation
Autodesk MapGuide Author Map Window File
.MWM Mail Warrior File
.MWP Lotus Wordpro 97 Smartmaster File
MegaWorks Pack File [Dutch]
.MWS Maple Spreadsheet
.MWV MovieWorks File
.MX3 Bitbop Tuner Locked Sound File
.MXD GIS Project File (map information)
.MXE Macro Express
Mindex Effect Album
.MXI Proteus File (personal light and sound stimulation system)
Macromedia Extension Information
Mindex Indices file for Indexed Images
.MXM MS Project/Outlook Team Assign Task
Mindex Master Index File for a Category
.MXP Macromedia Extension Manager
ArcReader Published Map
.MXT MS C
ArcMap Map Template
.MYD MySQL Data File
.MYI MySQL Data File
.MYDOCS MyDocs Drop Target
.MYP Make Your Point Presentation
.MYS Myst Saved Game
.MYW MyWorld Education Drawing
.MZ MOZART Music Document
.MZB MegaZeux Board
.MZF SHARP MZ-series Emulator File
.MZP MOZART Percussion File
.MZQ SHARP MZ-series Emulator QuickDisk File
.MZS SHARP MZ-series Emulator File
.MZT MOZART Template File
SHARP MZ-series Emulator File
.MZX MegaZeux World
