Hunting Duplicate Photos on a Mac Without Breaking the Library

Photos.app on macOS has a built-in duplicate finder that almost no one knows exists. A few third-party tools can also help, but some have quietly destroyed photo libraries by deleting originals. This guide covers the safe path: built-in finder first, then vetted third-party tools with review-before-delete behavior.

Key Topics Covered

• Photos.app Duplicates album — where it is and how to use it
• What Photos.app duplicate detection does and doesn't catch
• Third-party tools: vetted safe vs dangerous ones
• Near-duplicate detection for burst shots and slightly edited versions
• Safe export and backup before any cleanup
• iCloud Photos: how duplicates sync across Apple devices