Duplicate files · Choosing which copy to keep
What do the dates shown for each duplicate copy mean?
Short answer: Each copy shows when it was created and last modified on your Mac. Since the content is identical, the dates show each copy's history — when it was downloaded or copied — rather than which is the original. Use them with the folder to decide what to keep.
Each copy shows when it was created and last modified on your Mac. Because duplicates have identical content, these dates mostly tell you about the copy's history — when it was downloaded, copied or saved there — rather than which one is "the original".
Storage Studio's recommendation also takes into account when you last opened each copy, where it knows, along with whether it lives in a working folder or in Downloads or Desktop. Use the dates together with the folder each copy is in to decide which one you want to keep.