How to Compare Two Folders for Duplicate Files on Mac and PC

Rosa Reyes
time February 24, 2021 Preview 744
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There can be duplicate files between two folders. Duplicate files are useless in most cases. Also, they can take up precious storage space if there are a lot of them. This article will show you how to compare two folders and delete the found duplicate files all at once. By getting rid of unwanted duplicates, you can free up space on your computer. If you want to choose from which folder to remove the duplicates, you can also find detailed instructions on this in the article.

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How to compare two folders for duplicate files on Mac

If you are a Mac user, you can easily find duplicate files between two folders with Cisdem Duplicate Finder, the best duplicate file finder for Mac. Supporting all common file types and formats, it can find the duplicate photos, videos, audios, documents, archives and other types of duplicates in a single folder/drive or across multiple folders/drives.

Cisdem Duplicate Finder is safe and reliable to use. It uses advanced algorithms to compare files byte by byte and identifies true duplicate files based on file content. By default, it will remove the duplicates that you don’t want by moving them to Trash. This way, it’s possible to quickly and easily get them back if needed.

Main features:

  • Find all common types of duplicate files such as duplicate images
  • Support internal and external storage
  • Remove duplicates from Photos, iPhoto, iTunes and Music
  • Automatically select unwanted duplicate files for you to eliminate with 1 click
  • Easy to use and highly flexible
  • Provide a useful, up-to-date user guide
  • Support macOS 10.10 or later, including macOS 11 Big Sur

Free Download

Easy steps to compare two folders and find the duplicate files between them on Mac

Step 1. Download Cisdem Duplicate Finder for Mac and install it.

Step 2. Click the plus icon and add one of the two folders. Similarly, add the other folder. Click Scan.

add folders to compare

Tip: If you want to select from which folder to remove the found duplicates, click the settings icon in the corner, go to the Selection tab, and choose Select duplicates for removal from prioritized location.

Step 3. Once it finishes comparing the two folders for duplicate files, go to the All tab. View and preview the duplicate files.

view and preview

Tip: This duplicate file finder provides three preview modes, allowing you to preview images, videos, movies, music files and more. What's more, it lets you preview pictures side by side, which is very convenient, making it an excellent tool to find and delete duplicate photos on Mac.

Step 4. The app will automatically select duplicate files for you to delete all at once. If not happy with the auto-selection, you can select a desired selection rule.


Tip: If you are following the tip below Step 2, then here are a couple of things you need to do. Batch select all items under the All tab. Click the list icon and choose the selection rule Select by Priority.

Step 5. Click Delete.

Step 6. Click Yes to confirm.

Now there aren’t any duplicate files between the two folders on your Mac.

How to compare two folders and delete duplicate files on Windows 10 or earlier

If you are a Windows user, this part is for you. The software to be used is Ashisoft Duplicate File Finder. It supports Windows 10, 8.1, 8 and 7. You can use it to detect duplicate pictures, videos, music files and documents.

This duplicate finder brings the concept of the master folder and the target folder. When you are comparing two folders for duplicate files, one of them is the master folder and the other the target folder. Suppose File A exists in both folders. The two files are duplicates. You keep the File A in the master folder and delete the one in the target folder.

In the example, File G is duplicated in the target folder, but it’s not in the master folder. And the software will ignore it when comparing folders.

Step 1. Download Ashisoft Duplicate File Finder and install it.

Step 2. Open the software and choose Compare.

compare folders

Step 3. Go to the Master Folders tab and add the master folder. Add the other folder in the Target Folders tab.

Step 4. Click Start Search. And it will start comparing the two added folders and looking for the duplicate files between them.

Step 5. When it’s done, the found duplicate files will be listed. You can easily preview a file by selecting it in the list.

Step 6. Right-click any file in the list and choose the Select all in Target option that appears. You can also select them manually.


Step 7. Click Delete.

This method can help you find and delete the duplicate files between two folders. But there could still be duplicates in each folder.


When you compare two folders for duplicate files on your Mac or Windows PC, if there are only a few files in the folders, it’s possible to manually identify duplicates and get rid of the unwanted ones. But that’s not often the case. When it comes to folders containing tons of files, the best choice is to use duplicate file finder software. The methods described above are easy to follow. With them, you have control over how folders are compared and how duplicate files are deleted.

Rosa Reyes
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Rosa has worked in Mac software industry for more than eight years. She believes that the purpose of software is to make life better and work more productively. In addition to writing, Rosa is also an avid runner.

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