| uva | BRE U-value Calculator Data |
| uvd | LabControl Spectacle Binary Data |
| uvf | Netica Uncertain Value Format File |
| uvi | Yamaha Expansion Manager Library |
| uvkbk | PCData Back Backup Information |
| uvkey | Ultra Virus Killer License Key |
| uvl | µVision Signal Definition |
| uvla | µVision Signal Data |
| uvnts | UVScreenCamera Notes Data |
| uvr | 3DXML UVR Mesh Data |
| uvs | UVScreenCamera Segments Data |
| uvseg | UVScreenCamera Segments Data |
| uvt | DECE TTML Data |
| uvtsk | µVision Recorded Task-switching Data |
| uvtt | DECE TTML Data |
| uvutt | DECE TTML Data |
| uvw | Autodesk 3D Studio MAX UVW Coordinates |
| uvz | DECE ZIP Compressed Data |
| uwl | Corel WordPerfect User Word List |
| uwl | Novell GroupWise Custom Dictionary |
| uwrf | Universal Web Radio Data |
| uxd | Bruker RAW Data |
| uxd | URLBase URL Database |
| uxp | IGOR Pro Unpacked Experiment File |
| uxt | IGOR Pro Unpacked Experiment Template File |
| uxy | Barudan Embroidery Outline Data |
| uyl | User Screen Editor Dictionary Data |
| uz1 | JB BAHN Scenery Archive |
| uz2 | JB BAHN Scenery Archive |
| uz4 | JB BAHN Scenery Archive |
