auf

.aufAudacity Project File

Audacity · 2000

Developer
Audacity
Category
Audio
MIME Type
application/x-audacity-project
First Released
2000
Open Format
Yes
File Signature
Not a simple header; structured as a directory with .aup and _data folders.
At a Glance
.auf
Audacity Project File

An .auf file is a project file used by the Audacity audio editor to save your work-in-progress, not a final playable audio track.

Reviewed on July 14, 2026
Compression
Varies (internal audio data may be uncompressed or compressed depending on settings)
Transparency
N/A
Editability
High (within Audacity)
Best for
Audio project saving

Key Features

  • Preserves all editing steps and undo history.
  • Stores multiple audio tracks and their arrangement.
  • Allows non-destructive editing of audio content.
  • Acts as a container for your audio project's state.

Best For

  • Saving complex audio editing sessions in Audacity.
  • Maintaining the ability to undo or redo edits.
  • Keeping a record of all applied effects and their settings.
  • Continuing work on multi-track audio projects.

Less Ideal For

  • Sharing finished audio with others for listening.
  • Creating audio files for websites or streaming.
  • Directly playing audio in media players.
  • Importing into video editing software as a final audio track.

Common Use Cases

  • Saving an audio project mid-edit to resume later.
  • Archiving the source project for potential future revisions.
  • Collaborating on audio projects by sharing the project file.
  • Experimenting with different effects and edits without committing.

How to Open It

  1. Open the Audacity software.
  2. Go to 'File' > 'Open' or 'File' > 'Restore From (backup)' if prompted.
  3. Navigate to and select your .auf project file.
  4. Note: .auf files can only be opened and edited within Audacity.

What is a .auf file?

An .auf file is a project file created by the free and open-source audio editor Audacity. It's not a playable audio file but rather a workspace that stores all your editing information, including audio tracks, effects applied, and editing history. This allows you to revisit and continue working on your audio projects without losing any of your progress. When you're ready to share your final audio, you'll need to export it to a standard audio format like WAV or MP3.

Programs That Open .auf Files

PlatformProgram
WindowsAudacityFreeOfficial
macOSAudacityFreeOfficial
LinuxAudacityFreeOfficial

How to Convert .auf Files

FormatMethod
.WAVAudacity Export, FFmpeg
.MP3Audacity Export, FFmpeg, Online Converters
.OGGAudacity Export, FFmpeg

Common Problems with .auf Files

⚠️ Cannot open .auf file on a different computer or with other software.
.auf files are project files and only open in Audacity. Export your project to a standard audio format (like WAV or MP3) for playback or use in other applications.
⚠️ Lost or corrupted .auf project file.
Audacity creates backup project files. Check Audacity's backup directory or look for .bak files. Regularly saving and exporting is crucial.

Frequently Asked Questions

Is an .auf file an audio file?

No, an .auf file is an Audacity project file. It contains instructions and data for Audacity to reconstruct your audio project, but it's not a playable audio file itself. You must export your work to formats like MP3 or WAV for listening.

Can I play an .auf file directly?

No, .auf files are designed exclusively for Audacity. Media players cannot interpret this format.

Why is my .auf file so large?

Project files can be large because they store extensive editing data, undo history, and potentially uncompressed audio segments. The final exported audio file size will be much smaller.

Technical Details

The .auf format is a proprietary project file format specific to Audacity. Internally, it's structured as a directory containing several files, including a primary .aup file and an associated _data folder. The .aup file itself contains metadata about the project, while the _data folder holds raw audio chunks. This structure enables Audacity to non-destructively edit audio and retain undo history.

Did You Know?

Audacity itself is available on Windows, macOS, and Linux, making .auf files cross-platform compatible within the Audacity ecosystem.
The .auf format is designed to store a wide range of edits, from simple cuts and fades to complex multi-track mixing and VST plugin effects.

Security Information

Audacity is generally considered safe, but as with any software, always download it from the official website to avoid malware. .auf files themselves do not typically pose a security risk, but the audio data they reference could potentially contain malicious content if sourced from untrusted origins.

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