Find duplicate photos in your Lightroom library on Mac
Lightroom catalogs accumulate duplicate imports over the years. Here's how to find them without breaking the catalog.
Lightroom Classic doesn’t dedupe imports by default, and Lightroom CC’s “don’t import suspected duplicates” only checks filename and capture time. Import the same SD card twice with auto-rename on, and Lightroom happily creates a second copy of every RAW file. A few seasons of shooting and you’ve got hundreds of gigabytes of duplicate .NEF, .CR2, .ARW, or .DNG files scattered through your Pictures folder.
Two paths
The native way: Lightroom’s “Find Previous Process Photos” — sort of
Lightroom Classic has Library > Find Previous Process Version, but that’s not duplicates. It also has Library > Find Missing Photos, which is also not duplicates. There is no built-in “find duplicate photos in this catalog” command. You can sort by filename in Library view and eyeball matches, but RAW files often get auto-renamed on import, so filenames lie.
Some photographers use Smart Collections with criteria like “Filename contains -2” to catch Lightroom’s auto-rename pattern. That misses everything renamed on import or imported from different cards.
The Dupe way
Dupe operates on the files themselves, not the Lightroom catalog. That means it finds duplicate RAW files no matter what Lightroom called them or whether they’re in the catalog at all.
- Install Dupe and open it.
- Click “Add Folder” and select the parent folder where you store Lightroom-managed photos (commonly Pictures/Lightroom or a dedicated photos drive).
- Click “Scan.” Dupe hashes every RAW, JPEG, TIFF, PSD, and DNG file with SHA-256.
- Review duplicate groups. Each shows full paths so you can see which year/shoot folder a copy came from.
- Before deleting from disk, first go into Lightroom and remove the duplicate copies from the catalog (right-click > Remove Photo > Remove). Then move them to the Trash with Dupe.
Why remove from the catalog first? If you delete a file on disk that Lightroom still references, it’ll show up as a missing file with the question-mark badge. Doing it in catalog-then-disk order keeps things tidy.
What Dupe won’t do:
- It won’t flag a RAW and its corresponding JPEG sidecar as duplicates — different bytes, different files.
- It won’t flag two edits of the same photo (DNG vs original RAW) as duplicates — also different bytes.
- It won’t touch your
.lrcatcatalog file. Lightroom’s database is excluded. - It won’t touch XMP sidecar files unless those are byte-identical to other XMPs, which they usually aren’t.
Safety:
- All deletions go to the Trash, recoverable for 30 days.
- Hidden folders and the Lightroom catalog’s
Previews.lrdatapackage are left alone. - Byte-identical matching only — no AI guessing.
For most photographers, a single pass recovers 100+ GB of duplicate imports from forgotten card dumps.
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