| dmms | DropMind Map Style |
| dmmx | DropMind XML Map Bundle |
| dmn | SAS Stat Studio Metadata |
| dmnd | DIAMOND Data |
| dmnd | SonicSelector Data |
| dmo | TI Derive Demo |
| dmp | DB/TextWorks Exported Records File |
| dmp | Windows Memory Dump |
| dmpx | Oracle Database Application Dump |
| dmr | Inertial Explorer DMI Data |
| dms | WRAP DAY Message Data |
| dmsk | DivX Player Temporary Video Data |
| dmtemplate | Direct Mail Template |
| dmv | Adobe Acrobat Parsing Rules |
| dmw | Datamass Ag Data |
| dmx-info | DriverMax Driver Information |
| dmy | LTSTDB Time Series Data |
| dn | Adobe Dimension Model Data |
| dnb | Microsoft Windows Binary DNS Database |
| dnc | DANCE Database |
| dnd | ClustalW2 Guide Tree Data |
| dne | Netica ASCII Text Data |
| dnet | Netica ASCII Text Data |
| dnk | KillAd Data |
| dnn | DotNetNuke Manifest Data |
| dns | Microsoft Windows DNS Server Database |
| dntu | DameWare NT Utilities Data |
| dnw | EMPOP DrawNetWork Data |
| dock | DragThing Dock Data |
| dockpack | Stardock ObjectDock Package |
| docktheme | Stardock ObjectDock Theme |
| docmenx | Egis Encrypted DOCM Data |
| docmeta | Bukkit Information Data |
| docstore | Adobe Photoshop Lightroom Documentum Cache |
| dod | Progress Artix Data Services Data Model |