How Does the App Find Duplicates?

Duplicate Detective uses a multi-step process to accurately identify duplicate files on your Mac.

Step 1 -- Build the File Pool

The app collects all files from the folders you selected for scanning. Only files that meet or exceed the minimum file size threshold are included. By default, this threshold is set to 50 KB, but you can change it in the app's Settings.

Step 2 -- Compare File Hashes

Each file in the pool is assigned a unique hash value based on its contents. Two files that are byte-for-byte identical will always produce the same hash value, even if they have different file names or are stored in different locations.

This means Duplicate Detective finds true, exact duplicates rather than files that merely look similar.

Note: Two files can appear identical to the human eye and still not be considered duplicates. For example, two images may look the same but contain different metadata (such as EXIF data, timestamps, or color profiles). Because the metadata differs, the files produce different hash values and will not be flagged as duplicates.

Step 3 -- Present Results

Once all files have been compared, Duplicate Detective generates a list of all duplicate groups found. Each group contains two or more identical files. You can then review the results, preview files, and select which copies to remove.