| mscc | mSecure Data |
| mscg | Microsoft ClipArt Gallery for Mac Data |
| mscml | Media Server Control Markup Language File |
| mscx | mSecure Backup |
| msd | Map Service Definition |
| msd | Scream MiniSEED Data |
| msdl | Manchester Scene Description Language Data |
| mse-installer | Magic Set Editor Installer |
| msecure | mSecure Data |
| mseed | MiniSEED Data |
| msf | Altera Mask Settings File |
| msf | Mozilla Mail Folder Summary Data |
| msf | Miranda IM Skin |
| msg | SOBEK Communications Data |
| msg | SmartWare Intro Display Data |
| msg5 | Microsoft Graph 5 Data |
| msgstore | WhatsApp Saved Chat History |
| msh1xml | Windows PowerShell XML Data |
| msh2xml | Windows PowerShell XML Data |
| mshdb | Ministry Scheduler Pro Database |
| msif | MyLabel Designer Deluxe Data |
| msj | MicroSurvey CAD Temporary Data |
| msk | BrainVoyager QX Mask Data |
| msk | Affymetrix Mask File |
| mskin | Maxthon Browser Skin |
| mskn | MediaMonkey Skin |
| msmt | WNCS Measurement Data |
| mso | Microsoft Office Rendering Data |
| msor | FiberTrace Data |
| mspdi | Microsoft Project XML Data Interchange File |
