55 File Extensions starting with M
| .M1V | MPEG-1 Video |
| .M2TS | MPEG-2 Transport Stream Videos |
| .M2V | MPEG-2 Video |
| .M3U | MP3 Uniform Resource Locator |
| .M4A | MPEG-4 Audio File |
| .M4P | Protected AAC File |
| .M4V | MPEG-4 Video File |
| .M8 | Heretic II MipMap Image |
| .MAC | Mac Paint Image |
| .MACP | Mac Paint Image |
| .MAG | MAGIchan Graphics Image |
| .MANIFEST | Windows Assembly Manifest File |
| .MAP | DIV Game Studio Map Image |
| .MAP | Fenix Map Image |
| .MBFAVS | Stardent AVS X Image |
| .MBFS | Stardent AVS X Image |
| .MBM | Psion Serie 5 Bitmap Image |
| .MD5 | MD5 Checksum File |
| .MDF | MDF Disk Image |
| .MDI | Microsoft Document Imaging Image |
| .MDL | Half-Life Model Image |
| .MDS | MDS CD/DVD Image |
| .MET | OS/2 Metafile |
| .MGR | MGR bitmap Image |
| .MHT | |
| .MHTML | |
| .MID | MIDI Audio Sequence |
| .MIF | Image Magick file |
| .MIFF | Image Magick file |
| .MIL | Micro Illustrator Uncompressed Image |
| .MKA | Matroska Audio Stream |
| .MKV | Matroska Video Stream |
| .MNG | Multiple Network Graphics Image |
| .MNL | MathML Data |
| .MOD | MOD Audio File |
| .MOV | Apple QuickTime Movie |
| .MP | TeX Metapost Macro |
| .MP1 | MPEG-1 Audio Layer I |
| .MP2 | MPEG-1 Audio Layer II |
| .MP3 | MPEG-1 Audio Layer 3 |
| .MP4 | MPEG-4 Part 14 Multimedia Container |
| .MPEG | MPEG Video |
| .MPEG1 | MPEG-1 Video |
| .MPEG2 | MPEG-2 Video |
| .MPEG4 | MPEG-4 Video |
| .MPG | MPEG Video |
| .MPNT | Mac Paint Image |
| .MRF | Marks Russel File |
| .MRW | Minolta Raw Image File |
| .MSK | PaintShopPro Mask |
| .MSP | Microsoft Paint Image |
| .MTS | AVCHD Video File |
| .MTV | MTV Ray-Tracer Image |
| .MTX | Maw-Ware Textures Image |
| .MXF | Material eXchange Format |