Data recovery from external hard drive

External hard drives are a popular and convenient choice for expanding storage capacity, backing up important files, and transferring data between devices. However, like all digital storage devices, they are not immune to failure. Whether due to accidental deletion, physical damage, malware, formatting errors, or file system corruption, losing data from an external hard drive can be distressing. Fortunately, recovering lost data is often possible if you act quickly and follow the right steps.

1. Accidental Deletion

Files may be deleted accidentally by the user or a third-party program. On an external drive, once files are deleted, they often bypass the system Recycle Bin, making them harder to retrieve without specialized tools.

2. Formatting Errors

Formatting an external drive wipes out its file system, removing the index that tells your computer where files are stored. Whether intentional or accidental, formatting often results in total data loss—though the files themselves may still be physically present and recoverable.

3. File System Corruption

Improper ejection, sudden power loss, or virus attacks can damage the file system, making the drive unreadable. File system corruption can prevent access to the drive and may trigger errors such as “Drive not accessible” or “You need to format the disk before you can use it.”

4. Physical Damage

Dropping the drive, exposure to moisture, or extreme temperatures can damage internal components. Mechanical failures or damage to the USB port or controller board can render the drive unusable and make recovery more complicated.

5. Bad Sectors

Over time, hard drives develop bad sectors—areas of the disk that can no longer be read or written to. This can lead to slow performance, data corruption, and eventual data loss if too many bad sectors develop.

6. Virus or Malware Attacks

Ransomware, spyware, and other malicious programs can encrypt, corrupt, or delete files on an external hard drive. In some cases, malware can even prevent the drive from being recognized.

Signs Your External Hard Drive Might Be Failing

If you notice any of the following signs, your external hard drive may be on the verge of failure:

Clicking, grinding, or buzzing noises

Frequent disconnections or “device not recognized” errors

Extremely slow file transfers

Files or folders disappearing or becoming inaccessible

Unexpected requests to format the drive

Blue screen errors when plugging in the drive

Recognizing these signs early gives you a better chance to recover data before total failure occurs.

First Steps After Data Loss

If you’ve lost data from your external hard drive, time is of the essence. Here are the immediate actions to take:

1. Stop Using the Drive

Avoid writing new data to the drive, as this could overwrite the lost files. Even simple activities like opening the drive or running antivirus scans can make recovery harder.

2. Check Physical Connections

Ensure the USB cable is secure and undamaged. Try connecting the drive to another USB port or different computer to rule out connectivity issues.

3. Listen for Unusual Sounds

Strange noises from the drive especially clicking or grinding may indicate physical damage. If you hear these, shut off the drive immediately to prevent further harm.

4. Don’t Format the Drive

If prompted to format the drive, cancel the operation. Formatting erases directory structures, making data recovery more complex.

DIY Data Recovery Methods

If the drive is still physically functional and recognized by your computer, you can attempt data recovery using several methods.

Method 1: Check for Hidden Files

Sometimes files are not deleted but become hidden due to system errors or malware. To check:

Open File Explorer (Windows)

Click “View” and select “Hidden items”

Check if your lost files reappear

On macOS:

Open Finder

Press Command + Shift + . (period) to toggle hidden files

Method 2: Use the Command Prompt (Windows)

You can try restoring corrupted file systems using chkdsk:

Open Command Prompt as Administrator

Type: chkdsk E: /f (replace “E” with your external drive letter)

Press Enter and wait for the scan to complete

chkdsk can repair minor file system issues and potentially restore access.

Method 3: Check Previous Versions

On Windows, if File History or Restore Points were enabled:

Right-click the folder that previously contained the deleted files

Choose “Restore previous versions”

Browse available versions and restore the one that contains your data

Method 4: Use Data Recovery Software

If built-in tools fail, data recovery software is your next best option. These tools scan the drive at a low level to find remnants of deleted or lost files.

Features to look for in recovery software:

Deep scan capability

File preview before recovery

Support for multiple file systems (NTFS, exFAT, FAT32. HFS+)

Recovery from formatted or RAW drives

Popular recovery tools can recover:

Photos, videos, and documents

Email archives and system files

Partition structures

Steps:

Download and install recovery software (ideally on a different drive)

Launch the tool and select your external drive

Perform a quick scan, followed by a deep scan if needed

Preview and select files for recovery

Save recovered files to a different drive or location

When to Seek Professional Help

Not all data loss situations can be resolved with DIY tools. In cases of:

Physical damage (e.g., broken USB port, internal noise)

Logical damage from encryption or advanced corruption

Persistent read/write errors

Water/fire damage

You should consult a professional data recovery service. These specialists operate in cleanrooms and use advanced tools to recover data from severely damaged drives.

Things to look for in a reputable recovery service:

Free evaluation and diagnosis

No data, no charge policy

Certified cleanroom facilities

Transparent pricing

Keep in mind: Professional recovery can be expensive, but it may be the only option if the data is critical and not recoverable by software.

How to Prevent Future Data Loss

Data loss is always disruptive, but there are many ways to reduce the risk of it happening again.

1. Back Up Regularly

Use the 3-2-1 rule: Keep three copies of your data—two on different devices, and one off-site or in the cloud.

2. Safely Eject Drives

Always use the “Eject” or “Safely Remove Hardware” option before unplugging an external hard drive. This ensures all data operations are complete.

3. Protect from Physical Damage

Store external drives in padded, waterproof cases. Avoid exposing them to heat, moisture, or direct sunlight.

4. Install Antivirus Software

Keep your antivirus and antimalware tools updated to prevent infections that can corrupt or delete files.

5. Monitor Drive Health

Use tools like CrystalDiskInfo (Windows) or DriveDx (Mac) to monitor S.M.A.R.T. attributes and catch signs of failure early.

6. Avoid Overloading the Drive

Leave at least 10–20% of your drive’s capacity free. Drives that are nearly full tend to slow down and are more prone to errors.

7. Use Reliable Brands

Invest in well-reviewed, high-quality external hard drives that offer good warranties and proven reliability.

File System Types and Their Impact on Recovery

Different external hard drives may be formatted with different file systems, each with its own characteristics that impact recovery.

NTFS (Windows default)

Supports large file sizes

Journaling improves data integrity

Good recovery prospects with software

exFAT

Cross-compatible with Windows and macOS

Often used on flash drives and SD cards

Moderate recovery capability

FAT32

Older, limited to 4GB file size

Still common in older drives and removable media

Easy to recover from due to simplicity

HFS+ / APFS (macOS)

Native to Mac devices

APFS is more secure but harder to recover from

Specialized tools needed for Mac-formatted drives

Knowing your drive’s file system can help choose compatible software and recovery approaches.

Losing data from an external hard drive can feel like a nightmare, but recovery is often possible especially if you act quickly, stop using the drive, and use the right tools. DIY recovery methods can resolve many cases, from accidental deletions to logical file system errors. However, physical damage or complex corruption may require professional intervention.

Going forward, a proactive approach with regular backups, careful handling, and protective software can prevent data loss altogether. Your external hard drive is an important asset treat it with care, and it will serve you reliably for years.