How to Find and Delete Duplicate Files on Mac and External Hard Drives

When the service time of your Mac get longer and longer, the files stored in it will be more and more. Your Mac’s hard drives will run out of space. And you have to transfer some files to your external hard drives, but this method just masks the symptoms. And after you transfer files many times, your external hard drives may be a sea of duplicate photos, music files, archives, videos and other files. So how to find and delete duplicate files on Mac and external hard drives to free up disk space to store files with mac duplicate file finder.

What Bad Influences Will Duplicate Files Bring to You?

Before showing users how to find and duplicate files on Mac, let us talk about the bad influences that duplicate files will bring to Mac. Just imagine, if there are so many duplicate files on your Mac, what will happen?

At first, the time that you use to search target files will get longer. We all know, the more files you store in your Mac, the more difficult you find your files. What's more, there are a lot of duplicate files, which will make that harder. Obviously, it is likely to decrease your productivity if you let them stored on your Mac and external hard drives.

And then, other bad influence is that a large quantity of duplicates files will take a lot of hard disk space, which will make your Mac runs slower and slower and you will have no space to get update to OS X 10.12, even you can’t install more application. Those duplicate files hide in the corner you don't know, and gobble up your Mac and external hard drive space. And you have no more space to store other useful files. So how to find duplicate files on external hard drive mac? It’s time to do it!

Find and Delete Duplicate Files on Mac and External Hard Drives

Above is a question from a Mac user who wants to remove duplicate photos from Photos and external hard drives to free up disk space. Manually finding and removing duplicates on external hard drive mac or any other drive, is nearly an impossible task and very tedious. So why not ask for the help of some great duplicate finder software? In the mac app store, there are many free and paid applications.

# A Test among three duplicate finder applications

In the mac app store, we find three best duplicate finders with different price

1. Scan interface

To be honest, the interface of Gemini is the most wonderful and Cisdem Duplicate Finder is user-friendly.

2. Scan speed

Duplicate Detector – within 10 minutes

Gemini – within 20 minutes

Cisdem Duplicate Finder – within 15 minutes

The scan speed also depends on the size of your folder, but we can make sure that the Duplicate Detector with the quickest speed to complete the whole scanning process.

3. Scan result - Overview

The folder I added to scan stored most of mine pictures, I will pay more attention on it.

Size of image found in Cisdem Duplicate Finder – 522M

Size of image found in Geminni – 508.2MB

Size of image found in Duplicate Dector – cannot calculate (only show find 117.4 MB duplicates)

4. Scan result – preview

Click the detail information about the detail information of duplicates.

Cisdem Duplicate Finder – divide into eight categories

Genimi – divide into seven categories

Duplicate Dector – Put all duplicates at one interface

5. Delete setting

Cisdem Duplicate Finder – Support to delete duplicates into folder, recycle bin or delete permanently

Genimi – Support to delete duplicates into folder, recycle bin or delete permanently

Duplicate Detector – Support to delete duplicates into recycle bin

A contrast above three duplicate finder application, the Cisdem Duplicate Finder is the great comprehensive software. Next, we will introduce how to find and delete duplicates on mac and external hard drive.

# How to find and delete duplicates with Cisdem Duplicate Finder

Download free trial version of Cisdem DuplicateFinder below and follow below steps about how to find and remove duplicate files on Mac and external hard drives.

Steps to find and remove duplicate files on Mac and external hard drive

1. Connect your external hard disk to your Mac on which you have installed Cisdem DuplicateFinder. Then click “ + “ button to add your local Mac folders or external hard drive folders to scan. You can add multiple folders at the same time. Then click “ Scan “ button to start scanning your folders to find duplicate files. This duplicate file finder will show you real-time scanning results. You can stop scanning anytime you want.You can click the setting button on the top right corner to set up your file size or skip packages. And this app gives you two options to choose for erasing duplicate files from external hard drive; either move them to Trash or delete them permanently. These flexible scanning settings help you find and remove duplicate files at ease.
2. After the scanning process finishes, this duplicate file finder will show the final results. It will show how many files scanned and duplicates found on your Mac or external hard drive. Click “Show Results” and you will see a colorful pie chart. This colorful pie chart helps you classify duplicates and spot the most problematic file type.
3. This duplicate file finder will classify duplicates into 7 category and show in tab view. Click “All” on the tool bar and you will see all duplicates listed on the left column. You can use its built-in search function to search duplicates with keyword and sort files easily. You can preview every duplicate file by clicking it, and the detailed information will be shown on the right column.
4. After previewing all duplicate files, you can select duplicate files that you want to remove and hit “Delete” button on the lower right corner to delete duplicate files. If you want to delete all duplicate files from Mac or your external hard drive in one go, just click “Select All”. With Cisdem DuplicateFinder, you can delete all duplicates such as images, music, videos from your Mac or external hard drives.

More Tips on How to Find and Delete Duplicate Files on Mac

1. If you want to remove duplicates in iTunes, just open iTunes, click File and select Display Duplicates. And you can also press the Alt or Option key and click the View menu, select “Show Exact Duplicate Items”. Any duplicate items found will be displayed in the main iTunes window, allowing you to simply delete them as normal.

2. You can also use Finder to locate duplicates manually. Open a new Finder window. Enter the wild card asterisk symbol or keywords in the search field. Make sure the Size and Kind columns are displayed. Filter the results by Kind, and you will see the list of similar items. The process is rather slow because you need to manually decide which ones to keep and which to delete.

3. It is important to note that Cisdem DuplicateFinder can be used to find and remove duplicates from iPods.

4. Regularly manage your files and folders, this can help you find and delete duplicate files quickly.