| Extension | File Description |
| .MMM | Audio Files |
| .MMN | Uncommon Files |
| .MMO | Misc Files |
| .MMOD | Uncommon Files |
| .MMP | Data Files |
| .MMPBT | Uncommon Files |
| .MMPT | Uncommon Files |
| .MMQ | Uncommon Files |
| .MMR | Uncommon Files |
| .MMS | Uncommon Files |
| .MMSCRIPT | Uncommon Files |
| .MMSW | Uncommon Files |
| .MMT | Uncommon Files |
| .MMU | Uncommon Files |
| .MMV | Video Files |
| .MMW | Data Files |
| .MMX | Uncommon Files |
| .MMY | Uncommon Files |
| .MMZ | Uncommon Files |
| .MN0 | Uncommon Files |
| .MN1 | Uncommon Files |
| .MN2 | Uncommon Files |
| .MN3 | Uncommon Files |
| .MN4 | Uncommon Files |
| .MN5 | Uncommon Files |
| .MN6 | Uncommon Files |
| .MN7 | Uncommon Files |
| .MN8 | Uncommon Files |
| .MN9 | Uncommon Files |
| .MNA | Uncommon Files |
| .MNB | Uncommon Files |
| .MNC | Encoded Files |
| .MND | Uncommon Files |
| .MNE | Uncommon Files |
| .MNF | Uncommon Files |
| .MNG | Raster Image Files |
| .MNH | Uncommon Files |
| .MNI | Uncommon Files |
| .MNJ | Uncommon Files |
| .MNK | Uncommon Files |
| .MNL | Misc Files |
| .MNM | Uncommon Files |
| .MNN | Uncommon Files |
| .MNO | Data Files |
| .MNP | Uncommon Files |
| .MNPF | Uncommon Files |
| .MNQ | Uncommon Files |
| .MNR | Raster Image Files |
| .MNS | Settings Files |
| .MNT | Text Files |
| .MNU | Settings Files |
| .MNV | Uncommon Files |
| .MNW | Uncommon Files |
| .MNX | Misc Files |
| .MNY | Data Files |
| .MNZ | Uncommon Files |
| .MO | Developer Files |
| .MO0 | Uncommon Files |
| .MO1 | Uncommon Files |
| .MO2 | Uncommon Files |
| .MO3 | Audio Files |
| .MO4 | Uncommon Files |
| .MO5 | Uncommon Files |
| .MO6 | Uncommon Files |
| .MO7 | Uncommon Files |
| .MO8 | Uncommon Files |
| .MO9 | Uncommon Files |
| .MOA | Uncommon Files |
| .MOB | Video Files |
| .MOBAPP | Uncommon Files |
| .MOBDRV | Uncommon Files |
| .MOBI | Data Files |
| .MOBSKIN | Uncommon Files |
| .MOC | Uncommon Files |
| .MOCHA | Uncommon Files |
| Extension | File Description |
| .MOD | Video Files |
| .MODD | Video Files |
| .MODEL | CAD Files |
| .MODEM | Uncommon Files |
| .MODEM1 | Uncommon Files |
| .MODEM2 | Uncommon Files |
| .MODEM3 | Uncommon Files |
| .MODEM4 | Uncommon Files |
| .MODEM5 | Uncommon Files |
| .MODEM6 | Uncommon Files |
| .MODEM7 | Uncommon Files |
| .MODEM8 | Uncommon Files |
| .MODEM9 | Uncommon Files |
| .MODERNTALK | Uncommon Files |
| .MODS | Uncommon Files |
| .MODULAE | Uncommon Files |
| .module | Uncommon Files |
| .MODULES | Uncommon Files |
| .MOE | Uncommon Files |
| .MOF | Settings Files |
| .MOG | Uncommon Files |
| .MOGG | Uncommon Files |
| .MOH | Uncommon Files |
| .MOHO | Data Files |
| .MOI | Video Files |
| .MOJ | Uncommon Files |
| .MOK | Uncommon Files |
| .MOL | Data Files |
| .MOL2 | Uncommon Files |
| .MOM | Developer Files |
| .MON | Uncommon Files |
| .MONDAY | Uncommon Files |
| .MONEY | Data Files |
| .MONICA | Uncommon Files |
| .MONO | Uncommon Files |
| .MONS | Uncommon Files |
| .MONSTER2 | Uncommon Files |
| .MONTE | Uncommon Files |
| .MOO | Uncommon Files |
| .MOOD | Uncommon Files |
| .MOON | Uncommon Files |
| .MOOV | Video Files |
| .MOP | Uncommon Files |
| .MOQ | Uncommon Files |
| .MOR | Uncommon Files |
| .MORE | Uncommon Files |
| .MORTBATS | Uncommon Files |
| .MOS | Raster Image Files |
| .MOT | 3D Image Files |
| .MOTBIN | Uncommon Files |
| .MOTIF | Uncommon Files |
| .MOU | Compressed Files |
| .MOUNT | Uncommon Files |
| .MOUSE | Uncommon Files |
| .MOUSETEXT | Uncommon Files |
| .MOV | Video Files |
| .MOVE | Uncommon Files |
| .MOVEMON | Uncommon Files |
| .MOVERADDIN | Uncommon Files |
| .MOVERBACKU | Uncommon Files |
| .MOVERCONFI | Uncommon Files |
| .MOVERDB | Uncommon Files |
| .MOVERREG | Uncommon Files |
| .MOVERTEMPL | Uncommon Files |
| .MOVES | Uncommon Files |
| .MOVIE | Video Files |
| .MOW | Uncommon Files |
| .MOX | Data Files |
| .MOY | Uncommon Files |
| .MOZ | Web Files |
| .MOZART | Uncommon Files |
| .MOZEML | Uncommon Files |
| .MP | Vector Image Files |
| .MP+ | Uncommon Files |
| .MP0 | Uncommon Files |
