| mss | MediaShout Presentation Script |
| mss | Microprocessor Software Specification |
| mss | WRAP Message Data |
| mssp | mIRC Script Setup Creator Data |
| msstyle | Windows XP Unsigned Style |
| msstyles | Windows XP Style Data |
| mst | ChemFinder Chemical Structure Index Data |
| mst | Corel Presentations Master Template |
| mst | Gurobi Optimizer MIP Start Data |
| mst | Microsoft Visual Test Source Code |
| mst | Microsoft Windows Installer Transform |
| mstat | SAM Domain Output Data |
| mstr | MicroStrategy Dashboard Data |
| mstt | Prosa Minispecification Data |
| mstxt | Message Studio Text Data |
| msty | Muvee Automatic Video Editing Style |
| msv | MyStars! Saved View |
| msvp | eXtendable Wad Editor MSVP Data |
| msw | Corel Painter Color Mixer Settings Data |
| msw | Modbus Slave Workspace |
| mswallet | Microsoft Wallet Item Package |
| msxml | Mercury Motif Searches Data |
| msy | MicroSyn Data |
| msz | MediaMonkey v3 Compressed Skin |
| mt5 | Poser Material Data |
| mt940 | SWIFT MT940 Customer Statement Message |
| mta | Match! Answer Set Database |
| mta | Samsung AllShare Metadata |
| mtb | MediaTracker Database Backup |
| mtb | Minitab Exec File |
