File extensions that begin with M.
Ext. Type of file
M Objective C implementation
M1V MPEG movie
M3D Corel Motion 3D
M3U Playlist
M4A AAC - MPEG-4 audio
M4B AAC - MPEG-4 audiobook (protected)
M4P AAC - MPEG-4 audio (protected)
M4V iTunes Store videos
MAC MacPaint bitmap
MAK Visual Basic/MS C++ project
MAP Link editor map
MB1 Apogee Monster Bash
MBX Mailbox (email)
MCS MathCAD format
MCW Word for Mac document
MDB Access database
MEL Maya script
MET OS/2 Metafile
MEU Menu items
MGX Micrografx clip art
MDX dBASE IV multi-index
MID MIDI sound
MID Eudora script
MIL Same as GP4
MIX PhotoDraw
MKA Matroska audio
MKS Matroska subtitles
MKV Matroska video
MME MIME-encoded
MMF Microsoft mail
MMM Macromind animation format
MOBI Mobipocket e-book format
MOD Eudora script
MOV QuickTime movie
MP2 MPEG
MP2V MPEG
MP3 MPEG-1 Layer 3 audio
MP4 MPEG-4 file
MPA MPEG
MPE MPEG
MPEG MPEG
MPG MPEG
MPO 3D images (JPEG)
MPP Microsoft Project
MRK Informative Graphics markup
MRW Minolta RAW
MSC MS Management Console snap-in
MSCZ MuseScore music format
MSG Message
MSI Microsoft installer
MSO (oledata.mso) Rendering info for
Word documents attached in email
MSP Microsoft Paint bitmap
MSP Microsoft installer patch file
MUS Music
MUSICXML Music XML format
MVB Microsoft Multimedia Viewer
MXF Material Exchange Format (Pro-MPEG)
MXF Home Theater Master remote control