A resource fork is a part of a computer file used primarily on older Apple Macintosh systems. Unlike most files (which are made up of a single stream of data), files on these classic Mac systems could have two separate parts: a data fork and a resource fork.
The data fork is what most people think of as the actual contents of the file—text in a document, pixels in an image, and so on.
The resource fork, on the other hand, stores structured information that helps the system interpret or display the file properly. This can include things like:
Icons
Window layouts
Fonts
Menu definitions
Sounds or images associated with the application
These forks allowed developers to build more sophisticated applications and user interfaces by keeping certain pieces of data separate and easily editable.
Why is this important?
Although modern macOS and other systems no longer rely heavily on resource forks, they can still exist in older files, especially if you're working with archives or data from legacy systems. In some cases, transferring or extracting files without proper handling can result in loss of data stored in the resource fork.
This is relevant when processing files in eDiscovery, as certain metadata or visual elements (like icons or GUI elements) might reside in a resource fork rather than the main file data. If this information is important for your review or case, it’s good to be aware of how these forks work.
Can you still view or edit them?
Modern macOS systems can still recognize resource forks, though they are no longer central to how files are structured. There are also tools and editors that can help you inspect or manipulate resource fork contents, but they’re typically used in specialized workflows.