There can be duplicate files between two folders. Unnecessary duplicate files take up storage space and can lead to disorganization. This article will show you how to compare two folders for duplicate files and mass delete unwanted duplicates easily.
Cisdem Duplicate Finder
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If you are a Mac user, you can use Cisdem Duplicate Finder to quickly find duplicate files in and across folders and effortlessly remove duplicates.
Cisdem Duplicate Finder finds all types of duplicate files such as duplicate images and duplicate documents. It can scan your Mac and external storage devices for duplicate files. It can also search for duplicates in Photos, iPhoto, Music and iTunes.
You can use the app to scan one folder or multiple folders for duplicate files at a time. When scanning, it will compare all files, including those in subfolders (if any), and detect the identical ones.
1. Download and install Cisdem Duplicate Finder. The app is compatible with macOS 10.11 or later, including macOS Sonoma.
2. Click the plus icon 
and add the two folders that you want to compare.
3. Click Scan.
4. When it finishes comparing folders for duplicate files, the All tab will display all the duplicate files that are found. Sort, preview or view them if needed.
On the top right corner, you can change the preview modes to see detail information.
5. The app decides which duplicate files to remove for you, and automatically selects duplicates for mass removal. If you want, you can customize the selection manually or by choosing a selection rule 
.
6. Click Delete to delete selected files.
7. Click OK to confirm the deletion.
Now the deleted files go to Trash. And there aren’t any duplicate files between the two folders on your Mac.
After you finish the comparison, if you want to control from which folder to remove the found duplicate files, follow this tip.
In step 3, before you click the Scan button, go to Preferences 
. Click the Duplicate files tab. Select the Select duplicates for removal from prioritized location option. Click the plus icon and add the folders that you compare. Select the folder from which you’d like to remove duplicates, set a higher priority value such as 2. Select the other folder and set a lower priority value such as 1.
In step 5, highlight all items under the All tab with Command-A. Click the list icon and choose the Select by Priority rule.
Windows PC users can also use Cisdem Duplicate Finder to compare folders and delete duplicate files.
The app will take a look in your selected folders, compare the images, audios, videos, texts and all other files in the folders (including the ones in subfolders), and find duplicates based on content. You can then get rid of the unnecessary duplicates.
1. Download and install Cisdem Duplicate Finder. The app is compatible with Windows 10 (64-bit) and Windows 11.
2. Drag the folders that you are going to compare into the app.
3. Click Scan, and the app will start comparing folders and checking for the duplicate files in and across them.
4. Once the scan is done, you will be presented with the results window, which displays all the found duplicate files for you to view and sort.
5. Select the unneeded duplicate files to delete, which Cisdem Duplicate Finder has already done automatically.
6. Click Delete.
The deleted files will go to the Recycle Bin.
File Explorer also can be helpful for you to compare two folders and delete duplicate files. It is a file management app that built-in Windows. You can open it twice then navigate to the 2 folders you want to compare side by side (Windows + E keys to open the File Explorer).
First enter certain extension to the top right search box, such as .jpg.
Then sort the search results by Name.
After previewing and comparing the duplicate files in 2 folders, you can select the file to delete.
When you compare two folders for duplicate files on your Mac or Windows PC, if there are only a few files in the folders, you can manually identify duplicates and eliminate the unwanted ones. But that’s often not the case.
When it comes to folders containing tons of files, the best choice is to use duplicate file finder software. The steps described above are easy to follow. And you have control over how folders are compared and how duplicate files are deleted.
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.
HB
Hey, just wanted to drop a comment and say thanks. I appreciated the different methods that were offered. The instructions are super easy to follow.