.AU file extension
To open .AU files on Windows, right-click the .AU file and select 'Open with'.
.AU files are audio files that can be opened using compatible audio software. To open a .AU file, use a media player that supports this format.
Last updated: March 19, 2026 · Reviewed by Julian Stricker
What “reviewed” means on this page
- Format fit: whether the “what is this file?” description plausibly matches common real-world use of the extension, including category, typical MIME types, and aliases.
- Opening paths: whether Windows / macOS / Linux steps read plausibly for current OS dialogs and default apps. Not every step was tested on every OS version.
- Security framing: whether risk notes match the extension class (for example executables vs plain data) and whether affiliate wording does not contradict the security section.
- Sources and further reading: external links should point to vendors, standards bodies, or other primary references where possible; not every detail is individually sourced.
- Limits: this is clarity and safety-messaging QA, not a guarantee that every statement is exhaustive or that every binary you download is harmless. Pages without “Reviewed by” have not been through this editorial pass yet.
Full methodology in the Imprint — The Imprint also states where AI is used and what that does—and does not—replace.
Open on your device
Choose your operating system for a dedicated step-by-step opening guide.
How to open .AU files
Use these platform-specific instructions to open .AU files safely.
Windows
- Right-click the .AU file and select 'Open with'.
- Choose a compatible media player like VLC or Windows Media Player.
Mac
- Control-click the .AU file and select 'Open With'.
- Choose a compatible app such as VLC or QuickTime Player.
Linux
- Right-click the .AU file and select 'Open with'.
- Choose an audio player like VLC or Audacious.
iOS
- Open the .AU file in the Files app.
- Share it to a compatible app like VLC for playback.
Android
- Locate the .AU file in your file manager.
- Open it with a media player app like VLC.
Security notes
- Only open .AU files from trusted sources.
- Scan files for malware before opening.
- Avoid executing any embedded scripts within the file.
Can't open this file?
These are the most common causes and fixes when .AU files fail to open.
Common reasons
- File won't open
- Poor audio quality
Fix steps
- Ensure a compatible audio player is installed.
- Check the file integrity and re-download if necessary.
Recover a deleted or lost .AU file
If the file was deleted by mistake or the drive was formatted, data recovery software may be able to get it back. Stop writing to that drive right away, because new data can overwrite what you want to recover.
Windows software that recovers deleted or lost files from PCs and external drives such as HDDs, SSDs, USB drives and memory cards, after deletion, formatting or a crash.
Wondershare RecoveritWindows and Mac software that recovers deleted or lost files from computers and external drives such as HDDs, SSDs, USB drives and SD cards.
We may earn a commission when you use affiliate links. This supports our free file extension guides.
OS-specific troubleshooting
Convert .AU to other formats
Use conversion tools to change .AU files into formats your software supports.
What is a .AU file?
.AU is an audio file format originally developed by Sun Microsystems. It is commonly used for simple audio recordings and is supported by various audio playback applications.
Background
.AU files were developed by Sun Microsystems and are primarily associated with the Unix operating system. They were one of the first audio file formats used on the internet and are still supported by many audio playback applications today. The format typically contains simple audio data and is recognized by its '.au' file extension.
The AU format is known for its simplicity and was historically used in early web applications for embedding sound clips. It is less common today but remains supported by many modern audio players due to its historical significance and straightforward structure.
Users may encounter .AU files when dealing with legacy systems or older audio archives. Despite newer formats offering better compression and quality, the .AU format is still useful for basic audio playback and compatibility with older software.
Common MIME types: audio/basic
Further reading
Authoritative resources for more details on the .AU format.
Common .AU issues
File won't open
The file may not open if the required software is not installed or the file is corrupted.
- Ensure a compatible audio player is installed.
- Check the file integrity and re-download if necessary.
Poor audio quality
The audio quality might be subpar due to the file's original encoding.
- Try playing the file in a different audio player.
- Convert the file to a more modern format using an audio converter.
FAQ
Can I convert .AU files to another format?
Yes, use an audio conversion tool to convert .AU files to formats like MP3 or WAV.
Why does my .AU file sound distorted?
Distortion can occur if the file is corrupted or if the audio player does not fully support the format.
Similar file extensions
Compare related formats in the same category to find the right tool faster.