| Extension | File Description |
| .MDE | Plugin Files |
| .MDF | Misc Files |
| .MDG | Uncommon Files |
| .MDH | Uncommon Files |
| .MDHTML | Uncommon Files |
| .MDI | Page Layout Files |
| .MDJ | Uncommon Files |
| .MDK | Uncommon Files |
| .MDL | Audio Files |
| .MDM | Game Files |
| .MDMP | System Files |
| .MDN | Database Files |
| .MDO | Uncommon Files |
| .MDP | Settings Files |
| .MDPR | Uncommon Files |
| .MDQ | Uncommon Files |
| .MDR | Uncommon Files |
| .MDS | Disk Image Files |
| .MDT | Database Files |
| .MDU | Uncommon Files |
| .MDV | Uncommon Files |
| .MDW | Misc Files |
| .MDX | Disk Image Files |
| .MDY | Uncommon Files |
| .MDYV | Uncommon Files |
| .MDZ | Data Files |
| .MD_ | Uncommon Files |
| .ME | Text Files |
| .ME! | Uncommon Files |
| .ME0 | Uncommon Files |
| .ME1 | Uncommon Files |
| .ME2 | Uncommon Files |
| .ME3 | Uncommon Files |
| .ME4 | Uncommon Files |
| .ME5 | Uncommon Files |
| .ME6 | Uncommon Files |
| .ME7 | Uncommon Files |
| .ME8 | Uncommon Files |
| .ME9 | Uncommon Files |
| .MEA | Uncommon Files |
| .MEANT | Uncommon Files |
| .MEB | 3D Image Files |
| .MEC | Uncommon Files |
| .MED | Audio Files |
| .MEDIACONTR | Uncommon Files |
| .MEDIACTRL | Uncommon Files |
| .MEDIAONEPR | Uncommon Files |
| .MEDICAL | Uncommon Files |
| .MEDIU | Uncommon Files |
| .MEDLINE | Uncommon Files |
| .MEE | Uncommon Files |
| .MEEP | Uncommon Files |
| .MEF | Raster Image Files |
| .MEFP | Uncommon Files |
| .MEFS | Uncommon Files |
| .MEG | Data Files |
| .MEGABLASTE | Uncommon Files |
| .MEGAMISQUE | Uncommon Files |
| .MEH | Uncommon Files |
| .MEI | Uncommon Files |
| .MEJ | Uncommon Files |
| .MEK | Uncommon Files |
| .MEL | Executable Files |
| .MELL | Text Files |
| .MEM | Game Files |
| .MEMB | Uncommon Files |
| .MEMBERS | Uncommon Files |
| .MEMO | Uncommon Files |
| .MEMORY | Uncommon Files |
| .MEN | Uncommon Files |
| .MENTAL | Uncommon Files |
| .MENU | Game Files |
| .MENU1 | Uncommon Files |
| .MENU2 | Uncommon Files |
| .MENUS | Uncommon Files |
| Extension | File Description |
| .MEO | Uncommon Files |
| .MEP | Uncommon Files |
| .MEQ | Uncommon Files |
| .MER | Developer Files |
| .MERLIN | Uncommon Files |
| .MERMACK | Uncommon Files |
| .MERR | Uncommon Files |
| .MERRITT | Uncommon Files |
| .MES | Uncommon Files |
| .MESA | Uncommon Files |
| .MESH | 3D Image Files |
| .MESHWORLD | Uncommon Files |
| .MESSAGE | Uncommon Files |
| .MESSAGES | Uncommon Files |
| .MESSENGER | Uncommon Files |
| .MET | Data Files |
| .META | Video Files |
| .META4 | Web Files |
| .METAL | Uncommon Files |
| .METALFONT | Uncommon Files |
| .METALINK | Uncommon Files |
| .METHODS | Uncommon Files |
| .METS | Data Files |
| .MEU | Uncommon Files |
| .MEV | Uncommon Files |
| .MEW | Uncommon Files |
| .MEX | Data Files |
| .MEX4 | Uncommon Files |
| .MEXDS | Uncommon Files |
| .MEXHP3 | Uncommon Files |
| .MEXHP7 | Uncommon Files |
| .MEXN | Uncommon Files |
| .MEXRS6 | Uncommon Files |
| .MEXSG | Uncommon Files |
| .MEY | Uncommon Files |
| .MEZ | Uncommon Files |
| .MF | Font Files |
| .MF0 | Uncommon Files |
| .MF1 | Uncommon Files |
| .MF2 | Uncommon Files |
| .MF3 | Uncommon Files |
| .MF4 | Uncommon Files |
| .MF5 | Uncommon Files |
| .MF6 | Uncommon Files |
| .MF7 | Uncommon Files |
| .MF8 | Uncommon Files |
| .MF9 | Uncommon Files |
| .MFA | Developer Files |
| .MFASL | Uncommon Files |
| .MFB | Uncommon Files |
| .MFC | Uncommon Files |
| .MFD | Uncommon Files |
| .MFE | Uncommon Files |
| .MFF | Uncommon Files |
| .MFG | Uncommon Files |
| .MFH | Uncommon Files |
| .MFI | Uncommon Files |
| .MFJ | Uncommon Files |
| .MFK | Uncommon Files |
| .MFL | Data Files |
| .MFM | Uncommon Files |
| .MFMOD | Uncommon Files |
| .MFN | Uncommon Files |
| .MFO | Page Layout Files |
| .MFP | Uncommon Files |
| .MFQ | Uncommon Files |
| .MFR | Uncommon Files |
| .MFS | Encoded Files |
| .MFT | Data Files |
| .MFU | Uncommon Files |
| .MFV | Uncommon Files |
| .MFW | Plugin Files |
| .MFX | Plugin Files |
| .MFY | Uncommon Files |
| .MFZ | Uncommon Files |
