| Extension | File Description |
| .DNP | Uncommon Files |
| .DNQ | Uncommon Files |
| .DNR | Uncommon Files |
| .DNS | Game Files |
| .DNT | Uncommon Files |
| .DNU | Uncommon Files |
| .DNV | Uncommon Files |
| .DNW | Uncommon Files |
| .DNX | Uncommon Files |
| .DNY | Uncommon Files |
| .DNZ | Uncommon Files |
| .DO | Web Files |
| .DO$ | Uncommon Files |
| .DO0 | Uncommon Files |
| .DO1 | Uncommon Files |
| .DO2 | Uncommon Files |
| .DO3 | Uncommon Files |
| .DO4 | Uncommon Files |
| .DO5 | Uncommon Files |
| .DO6 | Uncommon Files |
| .DO7 | Uncommon Files |
| .DO8 | Uncommon Files |
| .DO9 | Uncommon Files |
| .DOA | Uncommon Files |
| .DOB | Developer Files |
| .DOC | Text Files |
| .DOC1 | Uncommon Files |
| .DOC2 | Uncommon Files |
| .DOC3 | Uncommon Files |
| .DOC4 | Uncommon Files |
| .DOC5 | Uncommon Files |
| .DOC6 | Uncommon Files |
| .DOC7 | Uncommon Files |
| .DOC8 | Uncommon Files |
| .DOCENX | Uncommon Files |
| .DOCGS | Uncommon Files |
| .DOCHTML | Web Files |
| .DOCKLET | Uncommon Files |
| .DOCKPACK | Uncommon Files |
| .DOCKTHEME | Uncommon Files |
| .DOCKZIP | Data Files |
| .DOCM | Text Files |
| .DOCMENX | Uncommon Files |
| .DOCMHTML | Web Files |
| .DOCS | Uncommon Files |
| .DOCTOR | Uncommon Files |
| .DOCU | Uncommon Files |
| .DOCUMENTAT | Uncommon Files |
| .DOCX | Text Files |
| .DOCXENX | Uncommon Files |
| .DOCZIP | Uncommon Files |
| .DOD | Uncommon Files |
| .DOE | Uncommon Files |
| .DOF | Uncommon Files |
| .DOG | Uncommon Files |
| .DOH | Uncommon Files |
| .DOI | Uncommon Files |
| .DOJ | Uncommon Files |
| .DOK | Uncommon Files |
| .DOL | Game Files |
| .DOM | Uncommon Files |
| .DON | Uncommon Files |
| .DOO | Uncommon Files |
| .DOP | Uncommon Files |
| .DOQ | Uncommon Files |
| .DOQQ | Uncommon Files |
| .DOR | Game Files |
| .DORE | Uncommon Files |
| .DOS | Uncommon Files |
| .DOSERRS | Uncommon Files |
| .DOT | Page Layout Files |
| .DOTHTML | Web Files |
| .DOTM | Text Files |
| .DOTMENX | Uncommon Files |
| .DOTX | Text Files |
| Extension | File Description |
| .DOTXENX | Uncommon Files |
| .DOU | Uncommon Files |
| .DOUBLEWIDE | Uncommon Files |
| .DOV | Backup Files |
| .DOVOICE | Uncommon Files |
| .DOW | Uncommon Files |
| .DOWN | Uncommon Files |
| .DOWNLOAD | Web Files |
| .DOWNLOADHO | Settings Files |
| .DOX | Developer Files |
| .DOX1 | Uncommon Files |
| .DOX2 | Uncommon Files |
| .DOX3 | Uncommon Files |
| .DOY | Uncommon Files |
| .DOZ | Uncommon Files |
| .DP | Uncommon Files |
| .DP$ | Uncommon Files |
| .DP0 | Uncommon Files |
| .DP1 | Uncommon Files |
| .DP2 | Uncommon Files |
| .DP3 | Uncommon Files |
| .DP4 | Uncommon Files |
| .DP5 | Uncommon Files |
| .DP6 | Uncommon Files |
| .DP7 | Uncommon Files |
| .DP8 | Uncommon Files |
| .DP9 | Uncommon Files |
| .DPA | Video Files |
| .DPB | Misc Files |
| .DPC | Uncommon Files |
| .DPD | Page Layout Files |
| .DPE | Uncommon Files |
| .DPF | Uncommon Files |
| .DPG | Video Files |
| .DPGRAPH | Uncommon Files |
| .DPH | Uncommon Files |
| .DPI | Uncommon Files |
| .DPJ | Uncommon Files |
| .DPK | Developer Files |
| .DPL | Developer Files |
| .DPLM | Uncommon Files |
| .DPLSAVE | Uncommon Files |
| .DPM | Plugin Files |
| .DPMI | Uncommon Files |
| .DPN | Data Files |
| .DPO | Uncommon Files |
| .DPP | Vector Image Files |
| .DPQ | Uncommon Files |
| .DPR | Developer Files |
| .DPS | Settings Files |
| .DPT | Data Files |
| .DPU | Uncommon Files |
| .DPV | Settings Files |
| .DPW | Uncommon Files |
| .DPX | Data Files |
| .DPY | Uncommon Files |
| .DPZ | Uncommon Files |
| .DP~ | Uncommon Files |
| .DQ0 | Uncommon Files |
| .DQ1 | Uncommon Files |
| .DQ2 | Uncommon Files |
| .DQ3 | Uncommon Files |
| .DQ4 | Uncommon Files |
| .DQ5 | Uncommon Files |
| .DQ6 | Uncommon Files |
| .DQ7 | Uncommon Files |
| .DQ8 | Uncommon Files |
| .DQ9 | Uncommon Files |
| .DQA | Uncommon Files |
| .DQB | Uncommon Files |
| .DQC | Uncommon Files |
| .DQD | Uncommon Files |
| .DQE | Uncommon Files |
| .DQF | Uncommon Files |
| .DQG | Uncommon Files |
