| mcdata | MCData XML Data |
| mcdb | Media Cache Database |
| mcf | MPRESS Control Format File |
| mcf | SignIQ Media Collection |
| mcfi | Autodesk Maya Initial Fluid Cache |
| mcfp | Autodesk Maya Fluid Cache Playback |
| mchelp | MadCap Flare DotNet Help Data |
| mcif | Macromolecular CIF File |
| mck | Macro Keys Encrypted Macro |
| mcl | MCell Cellular Automata Data |
| mcl | MUSHclient World Information |
| mcl | SmartCAM Macro File |
| mcmac | MasterCook Mac Document |
| mcml | Windows Media Center Markup Language File |
| mcp | Megacubo Package |
| mcpr | Minecraft Replay Mod Replay |
| mcr | Autodesk 3D Studio Max Macroscript |
| mcr | CuteFTP Script |
| mcr | General CADD Macro |
| mcr | MCreator Workspace |
| mcr | Perfect Keyboard Macro |
| mcr | Tecplot 360 Macro Data |
| mcreator | MCreator Workspace |
| mcs | Intel MCS-86 Hexadecimal Object |
| mcs | Mathcad Image Data |
| mcs | Maximal Compressed Structure |
| mcs | Pro/ENGINEER ModelCheck Start Configuration Data |
| mcsv | TouchGraph Navigator MCSV File |
| mct | Live Messenger Content |
| mct | MapChart Genetic Map Data |
| mcu | Nokia DCT4 MCU Firmware Flash Data |
| mcv | ManyCam Effect |
| mcx | MasterCook 5 Recipe Pictures |
| mcxe | MedicinesComplete Data |
| mcz | Poser Compressed Material Collection |
