.appledouble — AppleDouble Binary Format
Apple Inc. · 1990
A format designed to package macOS files with their resource forks and metadata for easier transfer to other operating systems.
Key Features
- Combines resource fork and data fork into one file.
- Preserves macOS Finder metadata (e.g., icons, comments).
- Facilitates cross-platform file transfers.
- Maintains file integrity and appearance across different OS.
Best For
- Ensuring macOS files retain their original icons and metadata on non-Mac systems.
- Transferring files that depend on resource fork data for functionality.
- Creating single-file archives of Mac-specific files for cross-platform use.
Less Ideal For
- General archiving or compression where only data fork content is needed (use .zip, .tar.gz).
- Storing simple text or data files that have no associated macOS metadata.
- When the target system natively supports macOS file forks (rare).
- Large media files where metadata preservation is less critical than file size.
Common Use Cases
- Emailing or sharing macOS files with Windows or Linux users.
- Archiving macOS files for long-term storage where metadata is critical.
- Transferring files via FTP or other protocols that don't handle Mac forks well.
- Bundling application resources and data for distribution.
How to Open It
- On macOS, most archive utilities (like The Unarchiver) can extract these files.
- On Windows or Linux, specialized tools like 'MacDrive' or command-line utilities can interpret the format.
- Some FTP clients might offer options to handle AppleDouble files during upload/download.
- Archive managers like Keka on macOS can also handle these files.
What is a .appledouble file?
The AppleDouble format is a way to bundle a file's resource fork and data fork into a single file, along with Finder information like icons and resource data. This is particularly useful when transferring files between macOS and other operating systems like Windows or Linux, which may not natively support macOS's two-fork file system. It ensures that essential metadata and resources accompanying a file are preserved during transfer, making it easier to work with macOS-generated files on non-macOS platforms.
Programs That Open .appledouble Files
| Platform | Program | ||
|---|---|---|---|
| Windows | MacDrive | Paid | |
| macOS | The Unarchiver | Free | |
| Keka | Free |
How to Convert .appledouble Files
| Format | Method |
|---|---|
| .ZIP | macOS Archive Utility, The Unarchiver, Keka |
Common Problems with .appledouble Files
Frequently Asked Questions
This is often a companion AppleDouble file containing resource fork data and metadata for the original file, generated by macOS for compatibility.
You usually cannot open it directly as a regular file. It needs to be processed by software that understands its structure to extract the original data and metadata.
No, it is not a compression format. It's a container format designed to bundle macOS file components for cross-platform compatibility.
Technical Details
AppleDouble files consist of two parts: an extended attribute section that stores resource fork data and Finder metadata, followed by the actual data fork content. This structure allows systems that only recognize a single data stream to correctly interpret and reconstruct the original macOS file, including its associated icons and metadata.