.APPLEDOUBLE File

The appledouble file extension is associated with the AppleDouble file format introduced with the first Apple Unix operating system called A/UX.

AppleDouble is similar to AppleSingle file format. However AppleSingle contains resources and data in one single file and AppleDouble in two separate files.

AppleDouble resources part with Finder meta-data has .appledouble file extension and data part is stored in original file format with original file extension. AppleDouble format is better for transport data through Internet, because non-Mac users can open the original file without other decoding like AppleSingle format.

AppleDouble file format is still supported by the Mac OS X. It is used to store Finder meta-data on drives with file systems that don't support resource forks, such as NFS and WebDAV.

Mime types:
multipart/appledouble

How to open:

Probably not meant to be accessed by the user.

How to convert:

Probably cannot be converted to anything else.