| sys | Windows System Configuration |
| t4 | TerrAlign Alignment Configuration |
| tam | Tame Settings |
| tbf | Cadvance Toolbar File |
| tbk | TQSL Configuration Backup |
| tccfgextender | TestComplete Tester-specific Settings Data |
| tci | TCINV Inversion Control File |
| tclogs | TestComplete Log Configuration File |
| tcls | TestComplete Configuration File |
| tcnet | TestComplete Configuration Reference File |
| tel | NCSA Telnet Configuration File |
| tf | Borland Turbo Configuration |
| tfd | TFSImage Settings |
| tgb | TheGreenBow VPN Client Configuration |
| thc | Therion Configuration File |
| timer | Systemd Service Timer Configuration |
| tiw | Bentley InRoads Wizard Settings Data |
| tlp | Tunnelier Profile |
| tlset | Text Locker Settings |
| tmap | TI PowerLAN Configuration |
| tn7 | Casio WK-3000 User Tones |
| toe | TouchDesigner Environment |
| tofp | Toshiba Fingerprint Utility Settings |
| tol | Zemax Tolerance Settings |
| tprc | Terminal-Plus Script |
| tps | Treepad Settings File |
| trm | Terminal Settings |
| tsi | NI Traktor Settings File |
| tsm | TwinCAT System Manager Configuration |
| ttcfg | SIMATIC Trace Configuration Data |
| ttcfgx | SIMATIC Trace Configuration Data |
| tvc | TeamViewer Configuration |
| tvf | dBASE Table View Settings |
| twc | TTWin Configuration File |
| twn | OP9630 Scanner Settings |