Dupe guide

After merging two folders on Mac, find the duplicates that got created

Finder folder merges can quietly create duplicates. Here's how to find and remove them safely.

4 min read

macOS Finder asks “Keep both” when you drag a folder onto another folder with the same name and the contents conflict. If you’ve ever clicked “Keep Both” instead of “Replace” — or if you used Terminal cp or rsync to merge folders — you’ve probably ended up with report.pdf and report 2.pdf, report 3.pdf, all sitting in the same destination folder.

What macOS actually does on a merge

When you drag a folder onto a folder of the same name:

The “Keep Both” path creates the duplicate situation this article is about.

Find the duplicates

  1. Install Dupe and open it.
  2. Click “Add Folder” and point it at the parent folder where you did the merge (or your whole home folder, if you don’t remember where).
  3. Click “Scan.” Dupe hashes every file with SHA-256 — duplicates with ” 2” or ” (copy)” suffixes will show up regardless of name.
  4. Browse the duplicate groups. Pairs with names like report.pdf and report 2.pdf are the smoking gun.
  5. Select the suffixed copies and click “Move to Trash.”

A nice property of Dupe here: it doesn’t care about filename pattern matching. Even if Finder renamed a file in a weirder way during the merge, or if you renamed something manually after the fact, Dupe still catches it because the bytes are identical.

A faster check for “obvious” rename duplicates

If you only want to handle the macOS-style 2 suffix renames specifically, you can search in Finder:

  1. In Finder, Cmd+F.
  2. Search 2. (with a leading space) within the merged folder.
  3. Review the results — most will be Finder-rename duplicates.
  4. Manually delete or verify with Dupe to make sure they’re actually duplicates of files in the same folder.

The Finder approach is faster but only catches the rename-style duplicates. Dupe catches every byte-identical pair regardless of name.

Safety

After a big folder merge, one pass usually cleans up dozens of 2 files in a few minutes.

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