External Drive Duplicate Finder: Clean Up Your External Drive

Find and Clean Up Duplicate Files on Your External Drive

With automatic duplicate file detection, easy view of detected duplicates, and automatic selection of duplicates for removal, this tool can help you easily clean up unwanted duplicates in bulk.

Duplicate photos, videos, audio, documents, and other files detected on an external drive

Detect Duplicate Files Accurately and Quickly

The tool can scan for duplicate photos, videos, audio, documents, archives, and other files on the external drive connected to your Windows or Mac computer. It also intelligently detects similar photos using on-device AI.

High accuracy: It identifies duplicate files by comparing file content, regardless of file names, providing high accuracy. It first generates a hash value (like a digital fingerprint) for each file based on its content, and then compares these values. If two files have the same hash value, they are duplicates.
Fast speed: The identification uses a fast hash algorithm called XXH3. In the test, this tool scanned a Samsung external SSD containing 1.43 million files (132.1 GB) and found 57.7 GB of duplicate files in just 3 minutes and 37 seconds.

Scan results window showing duplicate image groups and matching photo previews

Review Detected Duplicate Files Before Removal

When the scan is complete, the results window will appear, allowing you to easily view detected duplicate files all in one place or by file type, such as Document, Image, and Music. You can switch between three view modes for side-by-side image previews and basic file information.

Selection-rule panel, two groups of matched duplicate files with the copies auto-selected, and removal method options

Bulk Remove Duplicates with Automatic Selection

In each duplicate group, this tool automatically selects all but one file for removal based on the default Select by filename rule. You can choose a different selection rule or manually select or deselect files. No files will be deleted without your confirmation.

Various selection rules: There are multiple selection rules, based on filename, folder priority, or modification date (old or new). In addition to setting a desired rule as default, you can temporarily apply a rule to chosen groups in the current scan.
Multiple removal methods: For Windows users, selected files will be moved to the Recycle Bin or deleted permanently, and the method applied depends on the specific external drive. The confirmation message will indicate which method is used. For Mac users, selected files will be permanently deleted. Both Windows and Mac users can also move selected files to a local folder on the computer.

3 Easy Steps to a Duplicate-Free External Drive

Step 1: Scan

Drag the external drive connected to your Windows PC or Mac to the tool's interface. Click the Scan button.

Step 2: View

The results window displays duplicate files for you to view, sort, and search.

Step 3: Delete

Accept the automatic selections, or make adjustments manually or via selection rules. Click the Delete button, then confirm the deletion.

Important

During the entire process of scanning for and deleting duplicate files, please make sure that your external drive is well connected and don't remove it. When you remove your device after the process is complete, please eject your device properly instead of simply unplugging it.

Different Use Cases for This External Drive Duplicate Finder

With this tool, you can easily keep your external drive or certain folders on it free of duplicates. But some real-world use cases can be more complex or specific. Here are four common use cases.

Two external drives being scanned with a magnifier

Scan across multiple external drives

You can drag two or more external drives to the tool, or just add specific folders from each drive. If they contain a very large number of files, the scan may take longer. Using the Select by folder priority rule can help you delete duplicates on one drive while keeping files on another untouched.

Scan between external & internal drives

You can add your external drive and, for example, your PC's D: drive to the tool, or only add certain folders from them. The Select by folder priority rule also works in this case. The rule even allows you to keep files in a folder while removing duplicates elsewhere.

Duplicate photos on an external drive being reviewed

Find duplicate photos on an external drive

If you have a large external drive with lots of files and only want to find duplicate photos, you can choose the Images button before scanning. This way, the tool will only scan photos, which can also speed up the scan. You can focus on other file types, such as documents, videos, or both.

A photo library stored on an external drive

Deduplicate an external Mac photo library

If you are a Mac user who stores the Photos app library on an external hard drive, you can use this tool to remove duplicate and similar photos from this library. Before performing a scan, you first need to open this library in your Photos app. Deleted photos will be moved to the Recently Deleted album in the Photos app.

Find Duplicate Files on a Wide Range of External Drives

With support for a wide variety of external drives, Cisdem Duplicate Finder can be used as an external drive duplicate finder. This tool scans your entire drive or specific folders on it for duplicate files, helping you easily declutter storage and free up space.

External HDD, SSD, USB flash drive, and memory card

Support Different Types

External SSDs, external HDDs, USB flash drives, memory cards

External drives from WD, Seagate, LaCie, and Samsung

Support Different Brands

Western Digital, Seagate, SanDisk, LaCie, Samsung, and more

External drives with 500 GB, 1 TB, 2 TB, and 4 TB capacities

Support Various Capacities

16 GB, 128 GB, 500 GB, 1 TB, 2 TB, 4 TB, and more

Frequently Asked Questions

First, you need to connect this drive to your computer. Then, manually look for and delete duplicate files, or use software like Cisdem Duplicate Finder to help automate the process, especially if the drive has a lot of files.

There are two common ways. Do it manually using the Finder, where you sort files on this drive by file name, size, or type, and then manually compare files to identify duplicates. You can also do it using a duplicate file finder that supports external storage devices, which automatically identifies duplicates by comparing files based on content (hash values).

Before the scan, go to the tool's Settings. In the General tab, go to Ignore folders and files in the list. Click Add Folder to add your backup folder (or another important folder of your choice). Ignored folders will be skipped during a scan.

It depends.

If you have chosen the Move to folder removal method in Settings and set a local folder as the destination folder, duplicate files will be moved to and stay on your computer.

For Windows users, if the file system of your external drive is the same as your computer's, for example, NTFS, selected duplicate files will be moved to the Recycle Bin. If not, they will be deleted permanently.

For Mac users, selected duplicate files will be deleted permanently. However, there's an exception. If you are removing duplicates from a Photos app library stored on an external drive, deleted files will go to the Recently Deleted album and stay in this library and also your external drive for 30 days. After 30 days, they will be automatically deleted permanently.