| sds | Smart Diary Suite Database |
| sdt | Siemens Desktop Theme Data |
| sdtbx | XTRF Terminology Database |
| sdtid | RSA SecurID Software Token Import Data |
| sdts | Spatial Data Transfer Standard File |
| sdv | Smart Diary Suite Voice Data |
| sdv | WDK Static Driver Verifier Rules |
| sdw | Visual SourceSafe SDW Data |
| sdx | CaptiveWorks Satellite Receiver Channel Database |
| sdx | Kivuto Secure Download Manager Data |
| sdx | Smart Diary Suite Temporary Data |
| sdxf | Structured Data eXchange Format Data |
| sdxm | SDX Signed Data |
| sdxx | Autodesk AutoCAD Civil 3D Survey Database Extended Properties |
| sdy | Starmoney Database File |
| se1 | AD Summation iBlaze Database |
| sea | MAXQDA Saved Search |
| searchconnector-ms | Windows Search Connector Data |
| seawifs | SeaWiFS Data |
| sec | Concordance User Management Control Data |
| sec | Migration Wizard Secondary IFF File |
| sec | PGP Secret Keyring Data |
| sec | Pro/ENGINEER Sketch Data |
| sec | PTC Creo Section Data |
| seco | MSX Configurator Software Update |
| secstore | Adobe Acrobat Security Store File |
| sed | AutoCAD Civil 3D Superelevation Data |
| sedr | URAP Supplemental Experiment Data Record |
| see | LISCAD Database |
| seek | Word List Expert Seek List Data |
| seg | Mail.dat Segment File |
| seg | WaterGEMS Segmentation Analysis Results Data |
| seg2 | SEG-2 Data File |
| segd | SEG-D Data File |
| segy | SEG Y Data File |
