| .--- | Microsoft Corporation | Sikkerhedskopifiler | Windows Temporary File | MS-DOS | Microsoft Corporation |
| .001 | Smith Micro Software | Sikkerhedskopifiler | Split Archive File | Smith Micro StuffIt Deluxe | Smith Micro Software |
| .002 | Various Developers | Sikkerhedskopifiler | Split Archive Part 2 File | Smith Micro StuffIt Deluxe | Smith Micro Software |
| .003 | Welltek Software | Sikkerhedskopifiler | Split Archive Part 3 File | 7-Zip | Igor Pavlov |
| .006 | bhv | Sikkerhedskopifiler | Winfunktion Mathematik V8.0 Julia Fractal File | WinFunction Mathematics | bhv |
| .01B | Paychex, Inc. | Sikkerhedskopifiler | PenSoft Payroll Backup | Payroll | Paychex, Inc. |
| .022 | bhv | Sikkerhedskopifiler | Winfunktion Mathematik V8.0 Julia Fractal File | WinFunction Mathematics | bhv |
| .035. | bhv | Sikkerhedskopifiler | Winfunktion Mathematik V8.0 Julia Fractal File | WinFunction Mathematics | bhv |
| .036 | bhv | Sikkerhedskopifiler | Winfunktion Mathematik V8.0 Julia Fractal File | WinFunction Mathematics | bhv |
| .1-STEP | iOmega | Sikkerhedskopifiler | Iomega Backup File | Unknown Software | Unknown Developer |
| .14 | PTC | Sikkerhedskopifiler | Versioned Pro/Engineer Project File | Microsoft Windows | Microsoft Corporation |
| .1DK | IBM | Sikkerhedskopifiler | OS/2 Saved SKF Format | OS/2 | IBM |
| .201 | StarMoney | Sikkerhedskopifiler | StarMoney Agent Rollback File | StarMoney | StarMoney |
| .210 | StarMoney | Sikkerhedskopifiler | StarMoney Agent Rollback File | StarMoney | StarMoney |
| .2DK | IBM | Sikkerhedskopifiler | OS/2 Saved SKF Format | OS/2 | IBM |
| .3DMBAK | McNeel | Sikkerhedskopifiler | Rhino 3D Model Backup File | McNeel Rhino | McNeel |
| .6DK | IBM | Sikkerhedskopifiler | OS/2 Saved SKF Format | OS/2 | IBM |
| .73B | Texas Instruments, Inc. | Sikkerhedskopifiler | TI-73 Backup File | TI Connect | Texas Instruments, Inc. |
| .83B | Texas Instruments, Inc. | Sikkerhedskopifiler | TI-83 Backup Memory Image | TI Connect | Texas Instruments, Inc. |
| .92B | Texas Instruments, Inc. | Sikkerhedskopifiler | TiLP.Backup | TI-92 | Texas Instruments, Inc. |
| .AB | Google | Sikkerhedskopifiler | Android ADB Backup File | Google Android SDK | Google |
| .ABA | Palm | Sikkerhedskopifiler | Palm Address Book Archive | Palm Desktop | Palm |
| .ABF | Adobe Systems Incorporated | Sikkerhedskopifiler | Adobe Binary Screen Font File | Microsoft Windows Font Viewer | Microsoft Corporation |
| .ABK | Corel | Sikkerhedskopifiler | Automatic Backup File | Ability Office | Ability Plus Software |
| .ABU | ASUS | Sikkerhedskopifiler | Asus App Backup File | ASUS Backup | ASUS |
| .ABU1 | ASUS | Sikkerhedskopifiler | ASUS Backup File | ASUS Backup | ASUS |
| .ACP | Alfresco Software, Inc. | Sikkerhedskopifiler | Alfresco Content Package | Alfresco | Alfresco Software, Inc. |
| .ACU | Micro Focus International plc | Sikkerhedskopifiler | Machine Independent COBOL Object File | ACUCOBOL-GT | Micro Focus International plc |
| .ADI | Active@ Data Recovery Software | Sikkerhedskopifiler | Active@ Disk Image Backup File | Active@ Disk Image | LSoft Technologies Inc. |
| .ADK | IBM | Sikkerhedskopifiler | OS/2 Saved SKF Format | OS/2 | IBM |
| .AFI | AOMEI Technology | Sikkerhedskopifiler | AOMEI Backupper File Backup File | AOMEI Backupper | AOMEI Technology |
| .AIJ | Oracle Corporation | Sikkerhedskopifiler | Oracle Database After-Image Journal | Oracle Database | Oracle Corporation |
| .AJA | AJC | Sikkerhedskopifiler | Backup Revision Control Archive File | AJC Revision Archive | AJC |
| .AJL | CA Technologies | Sikkerhedskopifiler | ARCserve Backup Journal File | ARCserve Backup | CA Technologies |
| .ARC | Symantec Corporation | Sikkerhedskopifiler | Norton Backup Archive | Symantec Norton 360 Version 6.0 | Symantec Corporation |
| .ARM | Oracle Corporation | Sikkerhedskopifiler | MySQL Archive Storage Engine Metadata | MySQL | Oracle Corporation |
| .AS4 | askSam Systems | Sikkerhedskopifiler | AskSam Backup File | askSam Systems SurfSaver | askSam Systems |
| .ASD | Microsoft Corporation | Sikkerhedskopifiler | Word AutoSave File | Microsoft Word | Microsoft Corporation |
| .ASV | MakeMusic, Inc. | Sikkerhedskopifiler | Finale Auto-save File | Finale | MakeMusic, Inc. |
| .ATE | Microsoft Corporation | Sikkerhedskopifiler | Office Accounting Compressed Backup | Microsoft Office Accounting | Microsoft Corporation |
| .AWB | Nokia | Sikkerhedskopifiler | AMR-WB Audio File | Apple QuickTime Player | Apple |
| .AXR | Systems AXIS Ltd. | Sikkerhedskopifiler | AXIS Diplomat Report | AXIS Diplomat | Systems AXIS Ltd. |
| .BAC | Avantrix Inc. | Sikkerhedskopifiler | Backup Plus Backup File | Backup Plus | Avantrix Inc. |
| .BACKUP | Google | Sikkerhedskopifiler | Google Android Backup File | Google Android | Google |
| .BACKUP DEFINITION FILE | Willowsoft Creek Software | Sikkerhedskopifiler | Backup Definition File | Backup Made Simple | Willowsoft Creek Software |
| .BAK | Various Developers | Sikkerhedskopifiler | General Backup File | Microsoft SQL Server | Microsoft Corporation |
| .BAZ | Unknown Developer | Sikkerhedskopifiler | Acomba Accounting Suite Backup | Acomba Accounting Suite | ACCEO |
| .BBB | Reincubate | Sikkerhedskopifiler | BlackBerry Mobile Phone Backup File | Research In Motion BlackBerry Desktop Manager | BlackBerry |
| .BBK | Freebyte | Sikkerhedskopifiler | TreePad Backup File | Treepad | Freebyte |
| .BBZ | BitBlaze | Sikkerhedskopifiler | Bitblaze Audio File | Unknown Software | Unknown Developer |
| .BCA | Nemetschek Group | Sikkerhedskopifiler | Allplan Backup Catalog File | Allplan Engineering | Nemetschek Group |
| .BCK | Hewlett-Packard | Sikkerhedskopifiler | VMX Backup File | OpenVMS | Hewlett-Packard |
| .BCKP | Lavasoft | Sikkerhedskopifiler | Ad-Aware Quarantined File | Ad-Aware | Lavasoft |
| .BCM | Adobe Systems Incorporated | Sikkerhedskopifiler | Adobe Bridge Cache File | Adobe Bridge CC | Adobe Systems Incorporated |
| .BDB | Microsoft Corporation | Sikkerhedskopifiler | Microsoft Works Database Backup File | Microsoft Access | Microsoft Corporation |
| .BDF | Willowsoft Creek Software | Sikkerhedskopifiler | Backup Definition File | Backup Made Simple | Willowsoft Creek Software |
| .BEE | Andrew Filinsky | Sikkerhedskopifiler | Bee Archiver Compressed Archive File | BeeGui Bee Archiver | Andrew Filinsky |
| .BFF | IBM | Sikkerhedskopifiler | Backup File Format | AIX Toolbox | IBM |
| .BFW | SmartWare Corporation | Sikkerhedskopifiler | SmartWare Backup Cross-tab Definition | SmartWare | SmartWare Corporation |
| .BIF | MagicISO Inc. | Sikkerhedskopifiler | Boot Information File | MagicISO | MagicISO Inc. |
| .BJF | NTI Corporation | Sikkerhedskopifiler | NTI Backup Now Backup Job File | NTI Backup Now | NTI Corporation |
| .BK! | Corel | Sikkerhedskopifiler | Corel WordPerfect Document Backup File | Corel WordPerfect | Corel |
| .BK1 | Autodesk, Inc. | Sikkerhedskopifiler | Autodesk Backup File | Autodesk AutoCAD Ecscad | Autodesk, Inc. |
| .BK3 | Corel | Sikkerhedskopifiler | Corel WordPerfect Document Backup File | Corel WordPerfect | Corel |
| .BK4 | Corel | Sikkerhedskopifiler | Corel WordPerfect Document Backup File | Corel WordPerfect | Corel |
| .BK6 | Corel | Sikkerhedskopifiler | Corel WordPerfect Document Backup File | Corel WordPerfect | Corel |
| .BK8 | Corel | Sikkerhedskopifiler | Corel WordPerfect Document Backup File | Corel WordPerfect | Corel |
| .BK9 | Corel | Sikkerhedskopifiler | Corel WordPerfect Document Backup File | Corel WordPerfect | Corel |
| .BKC | Softland | Sikkerhedskopifiler | Backup4all Backup Catalog | Backup4all | Softland |
| .BKF | Microsoft Corporation | Sikkerhedskopifiler | Windows Backup Utility File | Microsoft Windows NT Backup - Restore Utility | Microsoft Corporation |
| .BKP | Various Developers | Sikkerhedskopifiler | Backup File | Zapback | Zaplots Games, Inc. |
| .BKU | Sage | Sikkerhedskopifiler | Timeslips Backup | Timeslips | Sage |
| .BKUP | cPanel | Sikkerhedskopifiler | Generic Backup File | cPanel and WebHost Manager | cPanel |
| .BKY | SmartWare Corporation | Sikkerhedskopifiler | SmartWare Backup Keyboard File | SmartWare | SmartWare Corporation |
| .BKZ | NCH Software | Sikkerhedskopifiler | FileFort Backup File | NCH FileFort | NCH Software |
| .BMK | return7, LLC | Sikkerhedskopifiler | BillMinder Backup File | return7 BillMinder | return7, LLC |
| .BPA | SimpleTech | Sikkerhedskopifiler | StorageSync Backup Archive | StorageSync | SimpleTech |
| .BPN | Graphisoft | Sikkerhedskopifiler | ArchiCAD Project Backup File | ARCHICAD | Graphisoft |
| .BPP | SoftVelocity | Sikkerhedskopifiler | Clarion Backup Application | Clarion | SoftVelocity |
| .BPS | Symantec Corporation | Sikkerhedskopifiler | BPS Programs Virus File | Kaspersky Anti-Virus | Kaspersky Lab |
| .BQY | Oracle Corporation | Sikkerhedskopifiler | Brio Query File | Internet Explorer | Microsoft Corporation |
| .BTX | SmartWare Corporation | Sikkerhedskopifiler | SmartWare Backup Text File | SmartWare | SmartWare Corporation |
| .BUC | Adobe Systems Incorporated | Sikkerhedskopifiler | Adobe Photoshop Elements Backup File | Adobe Photoshop Elements | Adobe Systems Incorporated |
| .BUP | Various Developers | Sikkerhedskopifiler | Backup File | Zapback | Zaplots Games, Inc. |
| .C000 | Genie | Sikkerhedskopifiler | Genie Backup Manager Compressed Split Backup | Genie Backup Manager | Genie |
| .C2C | VSO Software | Sikkerhedskopifiler | CopyToDVD Project File | CopyToDVD | VSO Software |
| .CAA | Synium Software Germany | Sikkerhedskopifiler | CleanApp Archive File | CleanApp | Synium Software Germany |
| .CBK | InterSystems | Sikkerhedskopifiler | Backup Configuration File | InterSystems Cache | InterSystems |
| .CBS | Pelican Accessories | Sikkerhedskopifiler | Code Breaker PS2 Save File | Mymc | Open Source |
| .CBU | Comodo Group | Sikkerhedskopifiler | Comodo Backup File | Comodo Backup | Comodo Group |
| .CDB | Nokia | Sikkerhedskopifiler | Symbian Phonebook Database | Nokia PC Suite | Nokia |
| .CK9 | DVO Enterprises | Sikkerhedskopifiler | Cook'n Cookbook Backup File | DVO Enterprises Cook'n | DVO Enterprises |
| .CLN | Microsoft Corporation | Sikkerhedskopifiler | Microsoft Windows 3.x Configuration Backup File | Microsoft Windows 3.x | Microsoft Corporation |
| .CMP | Microsoft Corporation | Sikkerhedskopifiler | Windows Connection Manager Profile | Microsoft Windows Server 2016 | Microsoft Corporation |
| .CRDS | Microsoft Corporation | Sikkerhedskopifiler | Windows CardSpace Backup File | Microsoft Windows 7 | Microsoft Corporation |
| .CSM | Autodesk, Inc. | Sikkerhedskopifiler | Character Studio Marker File | Character Studio | Autodesk, Inc. |
| .CTX | Microsoft Corporation | Sikkerhedskopifiler | Visual Basic Control Binary File | Microsoft Visual Studio | Microsoft Corporation |
| .CVT | ACD Systems | Sikkerhedskopifiler | Canvas External Tool File | Canvas X | ACD Systems |
| .C_ | Microsoft Corporation | Sikkerhedskopifiler | Microsoft Windows WinHelp Compressed Data | Microsoft Windows | Microsoft Corporation |
| .DA0 | Microsoft Corporation | Sikkerhedskopifiler | Windows Registry Backup File | Should Not Be Opened Manually | Unknown Developer |
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