| cvz | Card Vault Inventory Data |
| cw5 | CodeWallet Pro 5 Wallet |
| cw6 | COMPRESS Vessel Model File |
| cwa | Castelware Inventory Audit Data |
| cwm | Common Warehouse Metamodel File |
| cwr | WrapCandy Template |
| cww | Crossword Weaver Puzzle |
| cwx | CodeWallet Pro 5 Form |
| cxa | ANSYS Fluent Solution Animation File |
| cxc | Custody X Change Data |
| cxe | Common XML Envelope Data |
| cxf | Google Picasa Collage |
| cxf | Coordinates Export Format |
| cxf | SciFinder Chemical eXchange Format Data |
| cxi | Coherent X-ray Imaging Data |
| cxm | QuadColor Color Correction Master Data |
| cxml | Silverlight PivotViewer XML Data |
| cxp | Crocodile Physics Simulation Data |
| cxr | FMAT Plate Results Data |
| cxs | ConciseXML Format Data |
| cxt | Crocodile Technology Simulation Data |
| cxv | Custody X Change Data |
| cyd | LogXact Data |
| cyg | CyGem Pollux Data |
| cyl | Ribbons Cylinder Definition |
| cym | AdPlug Callus YM2151 Register Log |
| cyo | Clustify Output |
| cyp | Crocodile Physics Simulation Data |
| cys | Cytoscape Session File |
| cys | Clustify Summary File |
| cyt | Crocodile Technology Simulation Data |
| czp | ClozePro Archive |
| czr | Everest Advanced Report |
| d01 | MicroSim PCBoard Drill Data |
| d1 | Progress OpenEdge Database |
