| nc | Geopath NC File |
| nc1 | NewsLeecher Cache |
| nc1 | DSTV-CNC Data File |
| nc2 | NewsLeecher Cache |
| nc3 | netCDF Data |
| nc4 | netCDF Data |
| ncbr | Nitro Character Tile Data |
| ncc | Nokia PC Suite Content Copier File |
| ncd | PTC Creo CL Syntax Alias Data |
| ncdb | NoteCase Pro Database |
| ncde | NoteCase Pro Encrypted Database |
| ncer | Nitro Cell Resource |
| ncf | Xilinx Platform Studio Netlist Constraints File |
| ncg | Netomata Config Generator Template |
| ncgr | Nitro Character Graphic Resource |
| nch | Microsoft Outlook Express Folder Data |
| nci | Mastercam NCI Lines Data |
| nck | PTC Creo NC Check Image Data |
| ncl | PTC Creo CL Data |
| nclr | Nitro Colour Resource |
| nco | Nero BackItUp Compressed Data |
| ncomp | SAM Dirichlet Mixture Prior Library |
| ncp | Nikon Picture Control |
| ncp | SmartWare Communication Profile Data |
| ncs | Lotus Notes Content Source |
| ncsa | Hierarchical Data Format File |
| ncss | NCSS Dataset File |
| nc_ | Nero BackItUp Child File |
| nda | Nero BackItUp Drive Image |
| ndas | NDAS Exported Registration Data |
| ndb | NEPLAN Network Node Data |
| ndb | Act! Notes Database |
| ndd | Nikon Capture Dynamic Exposure Extender |
| ndf | Microsoft SQL Server Secondary Database File |
| ndf | Channel Data File |