| website | Internet Explorer Pinned Site Shortcut |
| wer | Windows Error Report |
| wflow | Automator Workflow |
| wfx | Total Commander File System Plugin |
| wht | Microsoft NetMeeting Whiteboard |
| wlms | Windows Live Movie Maker Script |
| wlmx | Windows Live Movie Maker Effect |
| wlpk | Renault R-Link Update Package |
| wlx | Total Commander Lister Plugin |
| workflow | Automator Workflow |
| wpe | WordPerfect Entrust Document |
| wsp | Adobe ImageReady Application Workspace |
| wta | Wintune Library |
| wtc | Logitech Webcam Watch File |
| wwd | Microsoft Works Wizard |
| wxm | wxMaxima Batch File |
| wxn | Waixing NES ROM Image |
| xe | XMOS Executable |
| xeo | Signwave Auto-Illustrator Extension |
| xfm | Adobe Audition XFM Plug-in |
| xia | Chiasmus Encrypted File |
| xis | Chiasmus Key File |
| xlnk | XML Link |
| xlsenx | Egis Encrypted File |
| xlx | XoloX File |
| xmwx | ExamSoft SofTest Working Data |
| xnk | Microsoft Exchange Public Folder Shortcut |
| xpt | Mozilla Firefox XPCOM Type Library |
| xrs | Real Player External Resource |
| xslic | XenServer License Data |
| xtea | XTEA Encyrpted Data |
| xtra | Adobe Director Xtra Extension |
| xuv | BlueFlash Firmware Image |
| xxc | Centraline COACH Controller Firmware |
| ybd | YobiDrive Link |
