| .S | Unknown Developer | File sviluppatore | Source Code File | Microsoft Notepad | Microsoft Corporation |
| .SBV | Superbase Software | File con layout di pagina | Superbase Form Definition File | Microsoft Notepad | Microsoft Corporation |
| .SCA | Symantec Corporation | File di dati | Norton AntiVirus Scan File | Microsoft Notepad | Microsoft Corporation |
| .SCR | Microsoft Corporation | File di sistema | Windows Screensaver File | Microsoft Notepad | Microsoft Corporation |
| .SCRIPT | Unknown Developer | File eseguibili | Generic Script File | Microsoft Notepad | Microsoft Corporation |
| .SCT | Scitex | File con immagini raster | Scitex Continuous Tone File | Microsoft Notepad | Microsoft Corporation |
| .SE | Unknown Developer | File di testo | Shuttle Document | Microsoft Notepad | Microsoft Corporation |
| .SFB | Sony | File di giochi | PlayStation 3 Disc Data File | Microsoft Notepad | Microsoft Corporation |
| .SHT | The Document Foundation | File web | HTML File With Server Side Includes | Microsoft Notepad | Microsoft Corporation |
| .SHTM | Opera Software | File video | HTML Server Side Include File | Microsoft Notepad | Microsoft Corporation |
| .SHTML | Sublime HQ Pty Ltd | File web | Server Side Include HTML File | Microsoft Notepad | Microsoft Corporation |
| .SIF | Microsoft Corporation | File di settaggi | Windows Setup Information File | Microsoft Notepad | Microsoft Corporation |
| .SKI | Motorola | File di settaggi | Motorola Phone Skin File | Microsoft Notepad | Microsoft Corporation |
| .SMD | Valve | File 3D | Valve Studiomdl Data File | Microsoft Notepad | Microsoft Corporation |
| .SMS | Sega | File di giochi | Sega Master System ROM | Microsoft Notepad | Microsoft Corporation |
| .SOUNDS | id Software | File di giochi | Quake 3 Engine Sound Definition File | Microsoft Notepad | Microsoft Corporation |
| .SPS | IBM | File di dati | SPSS Program File | Microsoft Notepad | Microsoft Corporation |
| .SQL | Various Developers | File di database | Structured Query Language Data File | Microsoft Notepad | Microsoft Corporation |
| .SRC | Unknown Developer | File sviluppatore | Source Code File | Microsoft Notepad | Microsoft Corporation |
| .SRX | Sublime HQ Pty Ltd | File di dati | SPARQL Query Results XML Format Result | Microsoft Notepad | Microsoft Corporation |
| .SS | Open Source | File sviluppatore | SilverStripe Source Code File | Microsoft Notepad | Microsoft Corporation |
| .SSC | Microsoft Corporation | File sviluppatore | SourceSafe Status File | Microsoft Notepad | Microsoft Corporation |
| .SSF | Unknown Developer | File video | Structured Subtitle Format File | Microsoft Notepad | Microsoft Corporation |
| .STC | Adobe Systems Incorporated | File web | Contribute Connection Key File | Microsoft Notepad | Microsoft Corporation |
| .STE | Adobe Systems Incorporated | File di settaggi | Dreamweaver Site Settings File | Microsoft Notepad | Microsoft Corporation |
| .SVH | IEEE Xplore | File sviluppatore | SystemVerilog Source Code Header File | Microsoft Notepad | Microsoft Corporation |
| .SVX | The Survex Project | File di GIS | Survex Cavern Data File | Microsoft Notepad | Microsoft Corporation |
| .SYSTEM | Open Source | File di giochi | Vega Strike Virtual System File | Microsoft Notepad | Microsoft Corporation |
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