| Extension | File Description |
| .MSB | Uncommon Files |
| .MSBCM | Uncommon Files |
| .MSC | System Files |
| .MSCML | Web Files |
| .MSCPC | Uncommon Files |
| .MSCR | Uncommon Files |
| .MSCX | Audio Files |
| .MSCZ | Audio Files |
| .MSD | GIS Files |
| .MSDEV | Uncommon Files |
| .MSDL | Uncommon Files |
| .MSDVD | Video Files |
| .MSE | Video Files |
| .MSEED | Data Files |
| .MSEQ | Data Files |
| .MSF | Misc Files |
| .MSG | Text Files |
| .MSG1 | Uncommon Files |
| .MSG2 | Uncommon Files |
| .MSG3 | Uncommon Files |
| .MSH | 3D Image Files |
| .MSHR | Uncommon Files |
| .MSI | Misc Files |
| .MSIF | Data Files |
| .MSJ | Uncommon Files |
| .MSK | Raster Image Files |
| .MSL | Uncommon Files |
| .MSM | Settings Files |
| .MSN | Settings Files |
| .MSNBAK | Uncommon Files |
| .MSO | Misc Files |
| .MSP | Raster Image Files |
| .MSPLG | Uncommon Files |
| .MSPX | Web Files |
| .MSQ | Uncommon Files |
| .MSR | Uncommon Files |
| .MSRCINCIDE | Misc Files |
| .MSS | Developer Files |
| .MSSTYLES | System Files |
| .MSSYTLES | Uncommon Files |
| .MST | Settings Files |
| .MSTY | Data Files |
| .MSU | Misc Files |
| .MSV | Audio Files |
| .MSVC | Uncommon Files |
| .MSW | Settings Files |
| .MSWMM | Video Files |
| .MSX | Uncommon Files |
| .MSY | Uncommon Files |
| .MSZ | Uncommon Files |
| .MS_ | Uncommon Files |
| .MT | Uncommon Files |
| .MT0 | Uncommon Files |
| .MT1 | Uncommon Files |
| .MT2 | Audio Files |
| .MT2S | Uncommon Files |
| .MT3 | Uncommon Files |
| .MT4 | Uncommon Files |
| .MT5 | Uncommon Files |
| .MT6 | Uncommon Files |
| .MT7 | Uncommon Files |
| .MT8 | Uncommon Files |
| .MT9 | Audio Files |
| .MTA | Misc Files |
| .MTB | Uncommon Files |
| .MTC | Uncommon Files |
| .MTD | Misc Files |
| .MTE | Audio Files |
| .MTF | Audio Files |
| .MTG | Uncommon Files |
| .MTG? | Uncommon Files |
| .MTGA | Uncommon Files |
| .MTH | Data Files |
| .MTHM | Uncommon Files |
| .MTI | Audio Files |
| Extension | File Description |
| .MTJ | Uncommon Files |
| .MTK | Uncommon Files |
| .MTL | 3D Image Files |
| .MTM | Audio Files |
| .MTN | Uncommon Files |
| .MTO | Uncommon Files |
| .MTOOL | Uncommon Files |
| .MTP | Audio Files |
| .MTQ | Uncommon Files |
| .MTR | Uncommon Files |
| .MTS | Audio Files |
| .MTT | Data Files |
| .MTU | Uncommon Files |
| .MTV | Video Files |
| .MTW | Data Files |
| .MTX | Plugin Files |
| .MTXDEF | Uncommon Files |
| .MTXT | Uncommon Files |
| .MTY | Uncommon Files |
| .MTZ | Uncommon Files |
| .MT_ | Uncommon Files |
| .MU | Uncommon Files |
| .MU0 | Uncommon Files |
| .MU1 | Uncommon Files |
| .MU2 | Uncommon Files |
| .MU3 | Uncommon Files |
| .MU4 | Uncommon Files |
| .MU5 | Uncommon Files |
| .MU6 | Uncommon Files |
| .MU7 | Uncommon Files |
| .MU8 | Uncommon Files |
| .MU9 | Uncommon Files |
| .MUA | Uncommon Files |
| .MUB | Uncommon Files |
| .MUC | Uncommon Files |
| .MUD | 3D Image Files |
| .MUE | Uncommon Files |
| .MUF | Data Files |
| .MUG | Uncommon Files |
| .MUH | Uncommon Files |
| .MUI | Audio Files |
| .MUJ | Uncommon Files |
| .MUK | Uncommon Files |
| .MUL | Uncommon Files |
| .MULTICALC | Uncommon Files |
| .MULTICL2 | Uncommon Files |
| .MULTICL3 | Uncommon Files |
| .MULTICLR | Uncommon Files |
| .MUM | System Files |
| .MUN | Uncommon Files |
| .MUO | Uncommon Files |
| .MUP | Data Files |
| .MUQ | Uncommon Files |
| .MUR | Uncommon Files |
| .MUS | Game Files |
| .MUSE | Web Files |
| .MUSIC | Uncommon Files |
| .MUSICXML | Data Files |
| .MUT | Uncommon Files |
| .MUTE | Uncommon Files |
| .MUU | Uncommon Files |
| .MUV | Uncommon Files |
| .MUW | Uncommon Files |
| .MUX | Audio Files |
| .MUY | Uncommon Files |
| .MUZ | Audio Files |
| .MV | Developer Files |
| .MV0 | Uncommon Files |
| .MV1 | Uncommon Files |
| .MV2 | Uncommon Files |
| .MV3 | Uncommon Files |
| .MV4 | Uncommon Files |
| .MV5 | Uncommon Files |
| .MV6 | Uncommon Files |
| .MV7 | Uncommon Files |
