Best Duplicate File Finder for External Drive

A duplicate file finder for external drive can efficiently remove redundant sync files to free up disk capacity. In this article, you’ll learn how to securely erase duplicate files from an external disk.

Lucas

By Lucas / Updated on July 10, 2025

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Why there are so many duplicate files on external drives?

Duplicate files are a common occurrence across both your computer, especially on external hard drives since many users use external drives as the backup drive for the main disk, and they are nearly unavoidable.

Duplicate files often accumulate on external drives for several reasons:

Multiple backups: Users frequently create multiple backups of their important data, either manually or through backup software. Over time, this can lead to redundant copies of files on the external drive.
Software glitches: Occasionally, software or applications may create duplicate files due to bugs or errors. For example, a synchronization tool might duplicate files during a sync process.
File compression: When users compress files to save space, the original files may still exist alongside the compressed versions. This results in duplicates, with the only difference being the file size.
Incomplete deletions: Sometimes, users attempt to delete files but fail to remove all copies, leaving behind duplicates.
File sharing and collaboration: When multiple users share an external drive for collaborative work, it's common for duplicate files to appear as different users may save their own copies.

However, regardless of the cause, it is imperative to address this issue. Eliminating duplicate files not only reclaims valuable storage space but also enhances file organization.

Manually delete duplicate files on external hard drive

Users on Windows may browse and search individual files in File Explorer, therefore manually identifying duplicate files on an external hard drive isn't difficult. Assume you want to delete such files manually/without using a duplicate file finder. In such a scenario, you can use the Windows File Explorer software to test the procedure.

While this method isn't usually practical on large hard disks, it does work if you carefully follow the procedures.

Step 1. After you connect your external/USB hard drive to the computer, open File Explorer by pressing the “Windows”+ “E” buttons on your keyboard.

Step 2. Navigate to the USB drive.

Step 3. Sort the files by Name, Date, or Size. Compare the files side-by-side to look for duplicates

Look for similar files by searching its names.

Search files

Rep this procedure until all comparable files have been deleted from your external or USB drive.

Efficient duplicate file finder for external drive to remove redundant files

If you’ve tried to use File Explorer to search files on your drive, you must know what disadvantages this built-in tool has. First, it’s quite slow. File Explorer is always slow at searching and it sometimes gets frozen during the searching process. Second, it may not find similar-sized files on your computer.

Therefore, for many inconveniences, many users turn to third-party duplicate file finder.

For locating and eliminating duplicate files, AOMEI Partition Assistant for Cleanup is unquestionably the best alternative. This tool allows Windows 11/10/8/8.1/7 and Windows Server users to swiftly scan and detect repetitious files while also allowing users to set up automated periodical cleaning programs on the device.

This software can handle a variety of files, including photographs, videos, music, documents, and archives, but it ignores key file types such as.dll;.lib;.sys; and so on.

AOMEI Partition Assistant for Cleanup

Free Up Disk Space To Keep Your PC Running Smoothly and Efficiently

Step 1. Initiate Find Duplicate Files. Install and launch AOMEI Partition Assistant for Cleanup. Click the "Find Duplicate Files" tab.

Find Duplicate Files

Step 2. Select a path to scan duplicate files. You can either click "Scan Now" to start the scan of your system C: drive. Or, click "Custom Scan" to manually select paths to be scanned. (Here, we take the "Custom Scan" as an example.)

Custom Scan

Step 3. After clicking "Custom Scan", all local and external drives on your PC will be displayed. You can also click the "Add Path" button, and then a browse folder window will pop up. So you can add more paths on this PC, like Desktop, Downloads, and other folder paths.

Add Paths

Step 4. Once necessary paths are added, you can click the "Scan Now" button to start the scan process.

Scan Now

Step 5. The scan process might take time. After the scan is complete, all duplicate files will be listed. You can click the button behind to locate them.

Locate Duplicate Files

Step 6. Select duplicate files to start deletion. You can either manually select duplicate files, or click the "Smart Select" button to automatically select unnecessary duplicate files to delete.

Tips: If the "Smart Select" is ticked, only the oldest duplicate file will be unticked. It means that all duplicate files except the oldest one will be ticked to delete. (The oldest file means the file that was created first. This file will not be deleted. All other duplicate files are considered copies of the oldest file. )

Smart Select

If you manually select all copies of duplicate files, you will get a pop-up warning window to keep at least one copy of the duplicate files. If you indeed want to delete all copies of duplicate files, you can click "OK" so all copies of duplicate files will be selected to delete.  

Warning

After unnecessary duplicate files are selected, please click the "Clean Now" button to start the deletion.

Clean Now

Step 7. Delete successfully. The deletion might take time. After the process is finished, the selected files will be deleted, and you will get a cleaning completed window displaying how much data you deleted in total. 

Clean Completed

Tips for avoiding duplicate files on external drive

It’s common that duplicate files appear on your external and internal drive, but we can do some maintenance to keep the accumulation of redundant files in a low level.

Organize your files
Create a well-structured folder hierarchy on your external drive to categorize files logically. Use descriptive file and folder names to make it easier to identify and locate items.
Regularly review and clean up
Periodically go through your files and delete unnecessary or outdated items. Consider setting aside time on a regular basis (e.g., monthly or quarterly) for file maintenance.
Use a duplicate file finder tool
Utilize duplicate file finder software to identify and remove duplicates. Run these tools periodically to scan your external drive for duplicate files.
Be mindful during file transfers
When you copy or move files to the external drive, check for existing copies to avoid unintentional duplication. If you're unsure, use the file management software's "Skip" or "Replace" options when prompted.
Implement version control
If you're working with documents that frequently change, consider using version control systems like Git for code or cloud-based collaboration tools for documents. These systems automatically manage versions, reducing the risk of duplicates.
Backup strategically
Plan your backup strategy carefully to avoid redundant copies. Consider incremental or differential backups that only save changes since the last backup. Regularly review and clean up old backup files.
File compression and archiving
When compressing files, keep track of the original files and delete them if they are no longer needed. This prevents duplicate copies of the same content in different formats.

By implementing these strategies and regularly maintaining your external drive, you can significantly reduce the accumulation of duplicate files.

What’s more, to keep your storage space organized and efficient, you can use disk management tool to manage your disk regularly. AOMEI Partition Assistant for Cleanup also provides PC Cleaner function to help you deeply clean disks.

To sum up

If you need to check duplicate files and need a duplicate file finder for external drive to remove these files from your computer, AOMEI Partition Assistant for Cleanup is your best plan.

FAQs about duplicate file finder for external drive

1. Why do I need duplicate file finder for external drive?
A duplicate file finder for an external drive is a software tool designed to identify and remove duplicate files on your external storage devices, such as hard drives or USB drives. You need one to free up storage space, enhance organization, and improve your drive's performance.

2. How does a duplicate file finder work on an external drive?
Duplicate file finders scan the contents of your external drive, comparing file names, sizes, and content to identify duplicate files. Once duplicates are found, you can choose to delete or move them, depending on your preferences.

3. How often should I run a duplicate file finder on my external drive?
The frequency of running a duplicate file finder depends on your usage patterns. It's a good practice to run it periodically, such as monthly or quarterly, to keep your external drive organized and free from duplicates.

4. Will using a duplicate file finder affect the performance of my external drive?
Using a duplicate file finder temporarily consumes some system resources while scanning for duplicates. However, this minor impact is outweighed by the long-term benefits of a cleaner and more organized external drive.

Lucas
Lucas · Staff Editor
I prefer peaceful and quiet life during vacation,but sometimes I watch football match if my favorite club performs brilliantly in that season. And I love reading, painting and calligraphy, thus I send my friends festival handwriting cards every year.