All about DUN Files

The DUN file type is primarily associated with Dungeon Defenders.

DUNFile Extension DUN
File extension: DUN
File type:  game data file

What is a DUN file?

DUN files mostly belong to Dungeon Defenders. A DUN file is used in specific game environments for storing level layouts and configuration data.
It is common in the following cases:

  • Game Level Data: Files from titles like Dungeon Defenders and Dungeon Siege store level design, environment settings, and object placements.
  • Alternate Use: In some instances, the same extension is used for dial‑up networking configuration files. This use is separate from its gaming role.
  • Usage: The file is processed by a game’s engine or its dedicated level editor. Manual editing with a text tool will not show meaningful content.
  • Format: They are typically binary files designed to be read by specific software.
  • Reference: More details can be found on this page.

FilExt.com note: Use the proper tool (such as a game editor or modding application) to open, view, or modify these files.

How to open DUN files

You need a suitable software like Dungeon Defenders to open a DUN file. Without proper software you will receive a Windows message "How do you want to open this file?" or "Windows cannot open this file" or a similar Mac/iPhone/Android alert. If you cannot open your DUN file correctly, try to right-click or long-press the file. Then click "Open with" and choose an application. You can also display a DUN file directly in the browser:. Just drag the file onto this browser window and drop it.

Online DUN Text Viewer

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Programs that open and convert DUN files:

  1. Dungeon Defenders
    See the previous paragraphs to learn more about the main application. DUN files are often referred to as Dungeon Defenders games because this type of file is primarily created or used by this software.
  2. Dial-Up Networking Export File
    Related links: DUN Info
  3. Dunce File

Technical Data for DUN File Extension

File classification:
Game
Related files:
Related links:

The following listing is compiled from the database produced by the 'Associate This!' program, selected data from the main FILExt database and file extension information submitted by users.

ProgramID: dunfile, FileType: Dial-Up Networking Exported file, AppName: Dial-Up Networking User Interface
EXEFile: RNAUI.DLL

ProgramID: dunfile, FileType: Dialup Networking File, AppName: Network Connections Shell
EXEFile: NETSHELL.DLL

ProgramID: dunfile
EXEFile: %SystemRoot%\system32\RUNDLL32.EXE NETSHELL.DLL,InvokeDunFile %1

ProgramID: dunfile
EXEFile: %SystemRoot%\SysWow64\RUNDLL32.EXE NETSHELL.DLL,InvokeDunFile


a dun game data file is a special file format and should only be edited and saved with the appropriate software.

How to solve problems with DUN files

  • Associate the DUN file extension with the correct application.
  • Update your software that should actually open game data files. Because only the current version supports the latest DUN file format. Search, therefore, e.g. on the manufacturer website after an available Dungeon Defenders update.
  • To make sure that your DUN file is not corrupted or virus-infected, get the file again and scan it with Google's virustotal.com.
  • Click here to open your .DUN file online - secure, fast, and no downloads needed.
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