| wcap | Mac OS X Wireless Diagnostics Captured Packets |
| wcat | WinCatalog Standard Database |
| wcb | WinCDR Data |
| wcd | Microsoft Works Calendar |
| wcf | WebEx Saved Chat Session |
| wcf | FRAMES Water Concentration File |
| wcinv | Windows Meeting Space Data |
| wck | WaterCAD Data |
| wcl | WinCatalog Light Database |
| wcmm | Bamboo Dock Application Data |
| wcrypt | Webcrypto-crypt Encrypted Data |
| wcs | WhopSee Compressed Skin |
| wct | WCT Reader Index File |
| wcu | CueCard Saved Flashcards Data |
| wcxf | WorldCard Mobile Exchange Data |
| wcz | Chameleon Clock Wallpaper |
| wd3 | Offline Explorer Data |
| wda | AutoCAD Electrical Project User Attributes Data |
| wdc | WinDaq Waveform Browser Data |
| wdc | SOBEK Wind Data |
| wdcd | Microsoft Word 5 for Mac Custom Dictionary Data |
| wdf | Renishaw WiRE Data |
| wdgp | Microsoft Word for Mac Add-in |
| wdh | WinDaq High Resolution Data |
| wdl | AutoCAD Electrical Project Labels Data |
| wdll | Microsoft Word 6 for Mac Add-in |
| wdmon | Mac OS X Wireless Diagnostics Monitor Data |
| wdn | AutoCAD Electrical Project Terminal Numbering Data |
| wdq | WinDaq Acquired Data |
| wdq | Offline Explorer Queue |