| tlset | Text Locker Settings |
| tm | Tecmail Configuration |
| tmap | TI PowerLAN Configuration |
| tn7 | Casio WK-3000 User Tones |
| toe | TouchDesigner Environment |
| tofp | Toshiba Fingerprint Utility Settings |
| tol | Zemax Tolerance Settings |
| top | Zemax Tolerance Settings Data |
| tprc | Terminal-Plus Script |
| tps | Treepad Settings File |
| tpx | TinyTERM Connection Settings Data |
| trm | Terminal Settings |
| tsi | NI Traktor Settings File |
| tsm | TwinCAT System Manager Configuration |
| ttb | BRLTTY Text Table Data |
| ttcfg | SIMATIC Trace Configuration Data |
| ttcfgx | SIMATIC Trace Configuration Data |
| tti | BRLTTY Text Subtable Data |
| tvc | TeamViewer Configuration |
| tvf | dBASE Table View Settings |
| tw3 | TCPWedge Configuration Data |
| twc | TTWin Configuration File |
| twn | OP9630 Scanner Settings |
| twn | TwinCalc Settings |
| twrps | TWRP Settings |
| txr | CorelDRAW Graphics Custom Settings Data |
| typeit4me | TypeIt4Me Clippings |
| tzi | Windows CE Time Zone Information |
| uae | WinUAE Configuration |
| uav | OpenPilot UAV Settings Data |
