How to recover lost files from a corrupted external backup drive

Backup & Storage KB-102

Summary

This guide helps you troubleshoot and resolve: How to recover lost files from a corrupted external backup drive. Follow the steps below to fix the issue.

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Common Causes

If your external backup drive has become unreadable or shows error messages, you may still be able to recover the lost files. This guide walks you through using Windows built-in utilities and reputable third-party recovery software to retrieve your data safely.

Critical warning: Stop using the drive immediately. Do not save new files to it, and do not attempt to write any data to the corrupted volume. Any additional writes can overwrite recoverable sectors and permanently reduce the chances of successful recovery.

If the data is critical, create a disk image or clone of the drive before running CHKDSK, repair commands, or recovery software. Working from an image protects the original drive from further stress and prevents accidental data loss during repair attempts.

Quick Fix Steps

Connect the external drive to a Windows PC using a known-good USB port.
Open Disk Management (press Win + X and select Disk Management) and confirm the drive appears and has a drive letter assigned (for example, E:). If it does not have a letter, right-click the volume and select Change Drive Letter and Paths to assign one.
Open File Explorer and note the drive letter.
If files appear after verifying the connection, copy them to a safe location immediately.
If the drive remains inaccessible, proceed to the detailed instructions below.

Detailed Instructions

1. Verify the Physical Connection

Try a different USB cable and a different USB port (preferably USB 3.0).
Connect the drive to another Windows PC to rule out a PC-specific issue.

Sometimes a loose connection is the only problem. Re-seating the cable can save you time.

2. Use Windows Built-in Tools

2.1 Run CHKDSK with Advanced Options

Before running CHKDSK, confirm the drive letter in Disk Management. Only proceed if you have created a disk image or clone, or if the data is not critical and you accept the risk of further data loss.

Press Win + X and select Terminal (Admin) or Command Prompt (Admin).
Type chkdsk E: /f and press Enter, replacing E: with your drive letter.
Allow the scan to complete. It will attempt to fix simple file-system errors.
When completed, review the summary. If it reports that Windows has recovered readable information, check the drive for your files.

The /r switch locates bad sectors and attempts recovery, but running it directly on a corrupted drive can cause further data loss. Do not run chkdsk /r on the original drive unless you have already imaged it or the data is not critical.

2.2 Use File History (if previously enabled)

File History restores files from its own backup location, not by navigating to the corrupted external drive itself. Use this method only if File History was previously configured to back up your data.

Open Settings → System → Storage → Advanced storage settings → Backup options (Windows 11), or Settings → Update & Security → Backup (Windows 10).
Select More options under Back up using File History.
Click Restore files from a current backup.
Browse the File History backup location for the files or folders you need.
Choose the items and click Restore to save them to a safe location on your internal drive.

3. Deploy Third-Party Recovery Software

3.1 Choose a Trusted Tool

Two widely used options are:

Recuva (free version sufficient for many cases)
EaseUS Data Recovery Wizard (the free trial is limited to 2 GB of recovered data; a paid licence is required for larger recoveries)

Deep scan and intensive recovery operations can stress failing hardware. If the drive is making unusual noises or is not reliably detected, create a disk image first and run recovery software against the image rather than the physical drive.

3.2 Install and Run Recuva

Download Recuva from the official website and run the installer.
Launch Recuva. The wizard opens automatically.
Select the file type you want to recover (for example, All Files for a full scan).
Choose On a specific location and enter the drive path E:\.
Check the box for Deep Scan to increase the chance of finding corrupted files.
Click Start. The scan may take several minutes to an hour.
When the scan finishes, review the results. Files marked in green are likely intact; yellow indicates partially recoverable.
Select the desired files, click Recover…, and choose a different drive (for example, your internal C: drive) as the destination.

3.3 Using EaseUS Data Recovery Wizard

Download the trial version from the EaseUS website and install it. Note that the free trial allows recovery of up to 2 GB of data only.
Open the program and select the corrupted external drive from the list of devices.
Click Scan. The software performs a quick scan followed by a deep scan automatically.
Use the preview pane to verify file integrity before recovery.
Select the check-box next to each file you wish to restore, then press Recover.
Specify a safe destination folder on a different physical drive.

Both tools create a temporary log of recovered files. Keep this log until you have verified the recovered data.

4. Verify Recovered Files

Open a sample of recovered documents, photos, and videos to ensure they open without errors.
Check file sizes against the original (if you have a record); a drastic size reduction often indicates corruption.
Run an antivirus scan on the recovered files before using them.

5. Prevent Future Drive Corruption

Eject Safely: Always use the Safely Remove Hardware icon in the system tray before unplugging the drive.
Power Protection: Connect external drives to a surge-protected power strip.
Regular Scans: Schedule a monthly chkdsk scan via Task Scheduler.
Multiple Backups: Keep at least two separate backup copies—one local (external drive) and one cloud-based (for example, Microsoft OneDrive for Business).
Health Monitoring: Use tools such as CrystalDiskInfo to monitor SMART attributes and replace drives showing signs of failure.

SSD vs HDD Considerations

Solid-state drives (SSDs) use the TRIM command, which can permanently erase deleted data blocks shortly after deletion or formatting. If you are recovering data from an external SSD, stop using the drive immediately and create an image before attempting any recovery. Once TRIM has run, recovery is often impossible even with professional tools. Traditional hard disk drives (HDDs) do not have this limitation, but they are more vulnerable to physical damage from drops and vibration.

Troubleshooting

Drive Not Detected

Check Disk Management (Win + X → Disk Management) for the drive’s status. If it shows “Offline” or “Unallocated,” do not initialize the disk if you need to recover data. Instead, note the disk number and contact a professional data recovery service.
Update the USB controller drivers via Device Manager → Universal Serial Bus controllers → Update driver.

Physically Damaged Drives

If the drive exhibits any of the following symptoms, stop using it immediately and contact a professional data recovery service:

Clicking, grinding, or beeping noises
The drive is not detected in Disk Management on multiple computers
The drive overheats during normal operation
The drive was dropped or exposed to liquid

Running recovery software or CHKDSK on a physically damaged drive can cause permanent platter damage or head crashes, making professional recovery impossible or significantly more expensive.

File System Shows RAW

Run chkdsk E: /f only if you have imaged the drive or the data is not critical.
Converting a RAW file system to NTFS usually requires formatting and will erase data. Avoid tools that claim to convert RAW to NTFS without data loss unless you have verified they operate at a sector level and you are working from a disk image.
Alternatively, use TestDisk (free, open-source) to rebuild the partition table, preferably against a disk image rather than the original drive.

Recovered Files Are Corrupt

Try a different recovery program—sometimes one tool can recover what another cannot.
Use the Repair feature in the recovery software (for example, EaseUS’s “Repair” button) to attempt file-level fixes.
If the data is critical, consider a professional data-recovery service.

Need Further Assistance?

If the steps above do not resolve the issue, please Open a Ticket and provide the following details:

Drive make and model
Exact error messages (screenshots if possible)
Steps already performed

Still Having Issues?

Need more help? If the issue persists after trying these steps, please open a support ticket and our team will assist you.

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