| .VMP | Sony | Ficheiros de Sistema | Logos Library System 2.x Verse Map | VAIO Movie Creator | Sony |
| .VRS | Corel | Ficheiros de Sistema | Corel WordPerfect Video Device Driver | Corel WordPerfect | Corel |
| .VXD | Microsoft Corporation | Ficheiros de Sistema | Windows Virtual Device Driver | Microsoft Windows | Microsoft Corporation |
| .VXX | Unknown Developer | Ficheiros de Sistema | IOsubsys | Unknown Software | Unknown Developer |
| .W31 | Microsoft Corporation | Ficheiros de Sistema | Windows 3.1 Startup Data | Microsoft Windows 3.x | Microsoft Corporation |
| .WCF | Microsoft Corporation | Ficheiros de Sistema | WebEx Saved Chat Session | Microsoft Notepad | Microsoft Corporation |
| .WDF | Workshare | Ficheiros de Sistema | Workshare Compare DeltaFile | Workshare Compare | Workshare |
| .WDGT | Opera Software | Ficheiros de Sistema | Opera Widget File | Opera | Opera Software |
| .WDPROJ | Microsoft Corporation | Ficheiros de Sistema | Microsoft Visual Studio Web Deployment Project File | Microsoft Visual Studio | Microsoft Corporation |
| .WDR | Psion PLC | Ficheiros de Sistema | Psion Series 3 Printer Driver | Symbian OS | Nokia |
| .WEBPNP | Microsoft Corporation | Ficheiros de Sistema | Web Point And Print File | Microsoft Windows | Microsoft Corporation |
| .WGZ | Nokia | Ficheiros de Sistema | S60 Web Runtime Widget Package | Nokia PC Suite | Nokia |
| .WPH | Phoenix Technologies | Ficheiros de Sistema | Phoenix BIOS File | Phlash16.exe | Phoenix Technologies |
| .WPX | Microsoft Corporation | Ficheiros de Sistema | Printer Description File 2 | Microsoft Windows | Microsoft Corporation |
| .WRS | Corel Corporation | Ficheiros de Sistema | Corel WordPerfect Windows Printer Driver File | Corel WordPerfect X8 | Corel |
| .WSS | Microsoft Corporation | Ficheiros de Sistema | Microsoft Windows Sound System File | Microsoft Windows | Microsoft Corporation |
| .XDSL | D-Link Corporation | Ficheiros de Sistema | D-link Router UK Firmware Update File | Unknown Software | Unknown Developer |
| .XFB | Apple | Ficheiros de Sistema | Xserve RAID Firmware Binary File | Apple Xserve RAID Admin | Apple |
| .XGT | Debian | Ficheiros de Sistema | Debian Template File | Debian | Debian |
| .XMO | Adobe Systems Incorporated | Ficheiros de Sistema | Adobe Authorware Movie Driver | Adobe Authorware | Adobe Systems Incorporated |
| .XMS | Alexander Gross | Ficheiros de Sistema | Music Studio Project | Alexander Gross Music Studio | Alexander Gross |
| .XRM-MS | Microsoft Corporation | Ficheiros de Sistema | Microsoft Security Certificate | Microsoft Windows | Microsoft Corporation |
| .XXT | Microsoft Corporation | Ficheiros de Sistema | Dynamic Link Library | Microsoft Visual FoxPro | Microsoft Corporation |
| .ZC | Eric Isaacson Software | Ficheiros de Sistema | Zipkey Configuration | Zipkey | Eric Isaacson Software |
| .ZEX | Zoom Corporation | Ficheiros de Sistema | ZOOM MRS-802 System File | MRS-802 | Zoom Corporation |
| .ZONE.IDENTIFIER | Microsoft Corporation | Ficheiros de Sistema | Microsoft Windows Zone Identifier File | Microsoft Windows | Microsoft Corporation |
| .ZUP | Microsoft Corporation | Ficheiros de Sistema | Microsoft Business Solutions Navision Configuration | Microsoft Dynamics NAV (Navision) | Microsoft Corporation |
| .~CU | Unknown Developer | Ficheiros de Sistema | Windows Cursor File | ACD Systems ACDSee | ACD Systems |
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