How to Make Data on External Hard Drive Unrecoverable?

Quick Navigation:

• Data Persistence and Recovery Methods – What You Need to Know?
• Basic Techniques to Make External Hard Drive Data Unrecoverable
• Advanced Methods to Make Data Unrecoverable on External Hard Drive
• Best Practices for Ensuring External Drive's Data Is Unrecoverable
• Verifying That External Drive's Data Is Unrecoverable
• Conclusion

Data security is an increasingly critical concern, especially when it comes to external hard drives. These portable devices often store vast amounts of sensitive information, including personal files, financial records, and business documents. However, when it's time to upgrade to a new device, sell your external hard drive, or simply dispose of it, making sure that your data is completely unrecoverable is essential.

Simply deleting files or formatting the drive doesn't guarantee that the information is gone for good. With the right tools, even novice users can recover deleted data, posing a significant security risk. Let us explore several ways to make data on an external hard drive unrecoverable, ensuring your information stays safe from prying eyes.

Data Persistence and Recovery Methods – What You Need to Know?

How Data Remains on External Hard Drives:

When you delete a file from an external hard drive, the operating system typically removes the file's reference from the file system directory. But until it is replaced by new data, the original data is still stored on the device. For this reason, deleted files are frequently recoverable with the use of specialist software. The file system doesn't immediately remove the current data; instead, it essentially designates the space formerly held by the deleted files as open for new data.

For example, in file systems like NTFS (commonly used on Windows) or APFS/HFS+ (used on macOS), deleting a file simply changes the file's status in the system, leaving the actual data intact on the storage medium. As long as the data hasn't been overwritten, it can be restored using various recovery techniques.

Common Data Recovery Techniques:

There are several methods that can be employed to recover data from an external hard drive, even after it has been deleted or the drive has been formatted:

• File Carving: This technique involves scanning the disk for file signatures, which allows recovery software to piece together and reconstruct files, even without the original file system structure.
• Partition Recovery: Even if the partition table has been damaged or deleted, recovery software can often reconstruct the original partitions and recover the files within them.
• Forensic Tools: Advanced tools used by professionals can recover data even from partially damaged or corrupted drives by examining the raw data sectors directly.

Understanding these techniques underscores the importance of ensuring that your data is truly unrecoverable before disposing of or selling an external hard drive.

Basic Techniques to Make External Hard Drive Data Unrecoverable

Using Simple Deletion and Overwriting:

One of the simplest methods to make data unrecoverable is by deleting the files and then overwriting the entire drive with new data. While this method is not the most secure, it can be effective for less sensitive data. Here's how you can do it:

• Delete the Files: Start by deleting all files on the external hard drive. Empty the recycle bin to ensure the files are no longer referenced by the operating system.
• Overwrite with New Data: You can then fill the drive with large, non-sensitive files such as videos or dummy data. This process overwrites the space previously occupied by your deleted files, making it harder for recovery software to retrieve the original data.

However, this method is not foolproof. Advanced recovery tools may still be able to retrieve fragments of the original data. For more sensitive information, more robust methods are required.

Encrypting the External Hard Drive:

Your external hard disk becomes much more secure if it is encrypted. Without the decryption key, no one will be able to access the data, even if it is recovered from the drive. Encryption transforms the data into a coded format, which is unreadable without the correct password or key.

Here’s how you can encrypt an external hard drive:

Windows:

• Use BitLocker (available on Pro and Enterprise editions): Right-click on the drive in File Explorer, select "Turn on BitLocker," and follow the prompts to encrypt the drive.
• Third-Party Tools: If you don’t have BitLocker, you can use software like VeraCrypt, which is free and offers strong encryption.

macOS:

• Use FileVault: Open System Preferences or System Settings, go to Security & Privacy, and enable FileVault for the external drive.
• Disk Utility: You can also use Disk Utility to format and encrypt the drive by selecting the "Encrypt" option during the formatting process.

By encrypting the drive, you ensure that even if the data is recovered, it remains inaccessible without the proper decryption key.

Advanced Methods to Make Data Unrecoverable on External Hard Drive

Securely Wiping the External Hard Drive: For more robust security, securely wiping the drive is the most effective method. This process overwrites every bit of data on the drive multiple times, making it impossible to recover the original information.

Using Built-In OS Tools [Data may be recovered]

Both Windows and macOS have built-in tools that can be used to securely wipe an external hard drive.

Windows Disk Management Tool:

Step 1. First, attach the external hard drive to your PC.

Step 2. Click the Start menu, then choose "Disk Management" to open Disk Management.

Step 3. Navigate to the external drive under the disks list.

Step 4. Choose "Delete Volume" by right-clicking on the partition you wish to erase.

Step 5. Use the Command Prompt to safely wipe the drive. Type diskpart into Command Prompt and hit Enter to launch it as an administrator. Next, to overwrite every sector on the drive, type list disk, choose the disk, and then use the clean all command.

macOS Disk Utility:

Step 1. Plug in the external hard drive to the Mac.

Step 2. Go to Applications, find Utilities and then Disk Utility.

Step 3. Choose the external hard drive from the list on the left.

Step 4. Click the "Erase" button and choose the "Security Options" to specify the number of passes for overwriting the data.

Step 5. Select the highest level of security for maximum protection, then click Erase to wipe the drive.

These built-in tools offer a secure method for wiping data, but they can be time-consuming depending on the size of the drive and the number of overwrite passes selected. And some of the formatted can be recovered by data recovery software.

Using Third-Party Data Erasure Software (Data is lost for good)

For those who need more advanced features or a more user-friendly interface, third-party data erasure software offers powerful options for securely wiping data on external hard drives. Once the data stored on the external hard drive is erased by data erasure software, the data is lost for good, cannot be recovered by any method.

DoYourData Super Eraser is a 100% safe, powerful and easy-to-use data erasure program. It can help you securely and permanently erase data from any external hard drive, ensure no data is recoverable.

It offers certified data erasure standards including HMG Infosec, NIST 800-88, Peter Gutmann's algorithm, DoD 5220.22-M, U.S. Army AR380-19 to help in securely and permanently erasing data from HDD, SSD, USB drive, Windows PC, Mac, memory card, RAID, Server, etc.

You can choose a data erasure mode to help you permanently erase data from your external hard drive before you sell, donate or give it to other people.

Mode 1: Erase Files/Folders

Click Add to add files/folders from the external hard drive to the erasure list, then click on Erase Now button to permanently erase these files and folders. No way to recover the erased files/folders.

Mode 2: Wipe Hard Drive

This mode will format and wipe the external hard drive and permanently erase all data (existing data, deleted/formatted/lost data included) from the external hard drive. Everything is lost for good, cannot be recovered by any method. This is the best way to prevent data recovery on external hard drive before you sell or donate your drive.

Mode 3: Wipe Free Space

This mode won't erase the existing files from the external hard drive. It wipes free disk space of the external hard drive and permanently erase all deleted/formatted/lost data from the drive.

Mode External Hard Drive Data Wiping Tools:

• DBAN (Darik's Boot and Nuke): This free tool is well-known for its ability to securely wipe entire drives. It runs from a bootable USB or CD and can be used on any connected external hard drive.
• Eraser: Eraser is a free and open-source tool for Windows that allows you to securely erase specific files or entire drives by overwriting them multiple times.
• CCleaner: In addition to its cleaning capabilities, CCleaner also offers a Drive Wiper tool, which can securely wipe free space or entire drives.

Best Practices for Ensuring External Drive's Data Is Unrecoverable

Multiple Overwrites:

One of the most secure methods for wiping data is to perform multiple overwrites. Each overwrite pass replaces the existing data with new data, making it increasingly difficult for any residual information to be recovered.

Recommended Overwrite Standards:

• Single Pass (Zero Fill): Overwrites the entire drive with zeroes. Adequate for most non-sensitive data.
• Three Pass (DoD 5220.22-M): A commonly used standard involving three passes—zeroes, ones, and random data. Suitable for moderately sensitive data.
• Seven Pass: Offers a higher level of security by performing seven passes. This method is often used for highly sensitive information but can be time-consuming.

Choosing the Right Method Based on Data Sensitivity:

Different types of data require different levels of security. When deciding how to make data on your external hard drive unrecoverable, consider the sensitivity of the information:

• Low Sensitivity: For general personal files, a simple overwrite or encryption may be sufficient.
• Moderate Sensitivity: Financial records or confidential documents should be wiped using a method like the DoD 5220.22-M standard.
• High Sensitivity: Government or corporate data may require seven-pass overwriting or even physical destruction.

By matching the method to the sensitivity of the data, you can ensure the appropriate level of security.

Verifying That External Drive's Data Is Unrecoverable

After wiping the external hard drive, it's important to verify that the data is indeed unrecoverable. You can use data recovery software to attempt to recover files and ensure that nothing can be retrieved.

Tools for Verification:

• Do Your Data Recovery Free: A free tool that can scan the drive to check if any deleted files can be recovered.
• TestDisk/PhotoRec: Open-source tools that recover lost partitions and files, useful for verifying that a wipe was successful.

By using these tools, you can confidently confirm that your external hard drive's data is truly unrecoverable.

Conclusion

Ensuring that data on an external hard drive is unrecoverable is a critical step in protecting your personal and professional information. Whether you're selling, repurposing, or disposing of a drive, the methods discussed in this article - from simple deletion and encryption to secure wiping and physical destruction - offer varying levels of security to meet your needs.

By following best practices, such as using multiple overwrite passes and verifying the effectiveness of your chosen method, you can rest assured that your data remains safe and secure. In a world where data breaches and identity theft are all too common, taking these precautions is not just advisable; it's essential.