External Hard Drive Corrupted and Unreadable Fixed without Data Loss

Position: How Tos - Disk Utilities- External Hard Drive Corrupted and Unreadable Fixed without Data Loss

Can external hard drive corrupted and unreadable issue be fixed? The 'drive is not accessible. The file or directory is corrupted and unreadable' error is common on external hard drives, and it can be caused by lots of reasons. Fortunately, the corrupted drive can be fixed without losing any data. In this page, you will learn how to recover files from corrupted and unreadable external HDD as well as how to fix a corrupted drive safely in Windows 10.

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Table of Contents

Overview on corrupted and unreadable external HDD fixes

"The external hard drive is no longer accessible and reports 'The file or directory is corrupted and unreadable'. The disk was formatted as one disk a while back and was only used to store files it was not used as a normal disk use. The unfortunate problem is that the USB cable was loose. So, every now and again it would cut the connection, but I did not realize. I used it again about four months ago to store more files and reorganize some folders… And I saw it was Starting and stopping so every night I would disconnect it and disconnect the power. At one point it would not switch on anymore. I bought an external case and the disk restarted OK. But the system recognizes the disk as RAW."

An external hard drive is regarded as one of the greatest data storage devices, as it provides large storage space to computers, making it quite convenience for data backup and file sharing. However, external hard drive may not be reliable as expected due to its portability, for it is more likely to get corrupted than local disk. Once an external hard drive gets corrupted and turns into unreadable, you will find that files, photos, songs, videos, etc. on it will be lost as well. How to tell if your external hard drive is corrupted? It is easy to know if an external disk does not work normally. When you connect it to computer, and you will find you cannot open it in File Explorer as usual. Also, Windows will pop up one of follow error messages:

  • H:\ drive is not accessible. The file or directory is corrupted and unreadable.
  • You need to format the disk in drive H: before you can use it. Do you want to format it?
  • H:\ is not accessible. The parameter is incorrect.
  • H:\ is not accessible. The volume does not contain a recognized file system. Please make sure that all required file system drivers are loaded and that the volume is not corrupted.
external hard drive corrupted and unreadable fix

Apart from receiving an error message, you will notice that the file system of the external hard drive becomes RAW in Disk Management. In a word, the external hard drive is corrupted and unreadable now. The positive side of the issue is that most corrupted external HDD is caused by logical damages, which means you can fix it on your own. However, if it is a physical damage, you will have to seek help of professionals. How to diagnose if an external hard drive is physically damaged? Here are some symptoms of physical damages:

  • External hard drive not detected: In Disk Management, the external HDD does now show up in Disk Management.
  • Strange sounds: There might be clicking noises after connecting the disk to computer.
  • Disk capacity changes to an unreasonable size, for example, a 1TB disk turns to 4GB.
  • Slow speed: The read/write actions is performed extremely slow, or even freezes computer.

Reasons behind external hard drive corrupted and unreadable issue

Before looking into fixes, it is necessary to have a clear understanding of causes behind the corrupted external HDD. By addressing the reasons, we can easily find out the most appropriate solutions. In brief, there is a list of common reasons that lead to external HDD corrupted and unreadable issue.

File system corrupted: an external hard drive is formatted as NTFS, exFAT or FAT32 file system. File system manages how and where a file is stored on the disk, once it gets corrupted, system will not be able to locate files. In general, the file system tends to get damaged if you do not use the Safely Remove Hardware before disconnecting USB drives. You need to inform Windows to complete write or read actions before removing an USB disk, otherwise, the file system is likely to get damaged.

Insufficient power supply: there might be something wrong with the enclosure, USB cable, or loose connection, and the result is that the disk cannot get enough power supply. Then system cannot read or write data on the disk.

Bad sectors: over time, an external HDD or other storage disk can develop bad sectors which can damage partition or data.

Physical damages: physical damages might be the result of dropping to the floor, clash, aging components, etc. Physically damaged disks cannot be fixed by solutions in this article, and you need to contact professional data recovery center if files are important to you.

Part #1: How to recover files from corrupted and unreadable external hard drive?

Note: Do not format the external hard drive before you are managed to recover all important files successfully. Data recovery should be carried out ahead of external HDD corrupted and unreadable fix.

In additions to diagnose whether the disk is logically damaged, you need to backup or recover files from the corrupted disk before proceeding with fixes. There is third-party software you can use to perform RAW partition recovery, corrupted external hard drive recovery, deleted file recovery, etc. Using such recovery software can get back lost files from corrupted drive even though you are lack of computer skills. When it comes to corrupted external HDD recovery software, it is strongly recommended to try DiskGenius. This software works on various inaccessible drives on hard drives, external HDDs, USB flash drives, SD cards, virtual disks, etc. and it allows you to preview recoverable files before registering it. Hence, you can verify if it can recover lost files correctly before purchasing a license code. The following content is the step-by-step of recovering files from corrupted external hard drive without formatting.

Step 1. Start DiskGenius, select the corrupted partition on your external hard drive and click File Recovery button. Then click Start button on the pop-up window to search for lost data from the drive.

You can easily locate the corrupted partition which is tagged with 'Damaged' or 'Unformatted' in the software. The word 'Damaged' here means the drive might be either logically or physically damaged.

There is a Partition Recovery button next to File Recovery, and that option is for lost/deleted partition recovery instead of corrupted partition recovery. Hence, the correct option is File Recovery.

external hard drive corrupted and unreadable fix

Reminder: As to corrupted NTFS partition, you can try "Load Current Partition Intelligently" before running File Recovery. This function is especially designed for corrupted NTFS drives, and it can load files with original names rapidly as long as the partition is not damaged very badly.

external hard drive corrupted and unreadable fix

Step 2. Wait for the scanning to finish.

You may need to wait for long time if the partition being scanned is very large. The scanning process lists found files, and you can view files to see if wanted files are found. Also, there is Pause and Stop button, which allows you to either pause or stop scanning anytime you want. Once the scanning stops or pauses, you can copy found files to a different drive.

external hard drive corrupted and unreadable fix

Step 3. Preview files to estimate recovery result.

You can expand directory on the left pane and view files on the right, and you can have a general idea of files to be recovered; Double-click a file on the right pane, and you can view file content on the preview window, as the picture below. By preview files, you can estimate whether the file can be recovered correctly. If the preview shows the file is corrupted and preview fails, the file will be corrupted after recovery.

external hard drive corrupted and unreadable fix

Step 4. Recover files you want.

Select files and folders you need, right-click on selected data and choose Copy To option copy them to a safe location.

external hard drive corrupted and unreadable fix

Bonus tips to protect external hard drive from getting corrupted and unreadable

  • Safely eject USB drive each time before removing it from computer. Since the improper removal of USB drive is major cause of corrupted drive, it is necessary to attach importance to such actions to avoid RAW drive.
  • Place external HDD is a safe place and keep it away from any damages. Also, you should handle it gently especially when it is connected to your computer. It is easier to get damaged when heads in the external hard drive is in working status.
  • Install anti-virus software or enable Windows Defender on your computer. External hard drive can infect virus or malware when it is used on a computer that is not protected by anti-virus software. Some virus is able to corrupt partition, data or even operating system.
  • Create backups for important data. It is suggested to create backups for important files and keep more than one copy of backups. Thus, you can retrieve data from backup when you run into a corrupted disk.

Part #2: How to fix a corrupted external hard drive? – 3 fixes

There is possibility that your external hard drive is not damaged that bad, so you do not have to rush to the repair center. First, you can try repairing a corrupted external hard drive by yourself, and the following part lists common fixes. Before trying these fixes, you need to have a check of these aspects:

  • Check the power supply: you can determine if the power supply works well by connecting the corrupted and unreadable external hard drive to another computer. If it gets same error, fixes should be carried out.
  • Connect the corrupted external HDD with another USB cable: the old USB cable might be broken. Also, try it on different USB ports.
  • Important files on the external HDD have been recovered to a safe location, for following fixes might remove or even overwrite data on the disk.

Here are solutions on external hard drive corrupted and unreadable fixes:

Solution #1: Format the corrupted/unreadable drive to NTFS/FAT32/exFAT/EXT4 using DiskGenius Free

Step 1. Install and launch DiskGenius Free Edition on your computer and connected the corrupted external hard drive to this computer as well.

Step 2. Right-click the corrupted drive in DiskGenius and choose "Format Current Partition".

external hard drive corrupted and unreadable fix

Step 3. Choose a file system you want to use and click "Format" button. Then click "Yes" to start the formatting process.

external hard drive corrupted and unreadable fix

DiskGenius supports to format a partition to NTFS/FAT32/exFAT/EXT4/EXT3/EXT2 no matter the size of the drive.

Solution #2: Format the corrupted and unreadable external disk with Disk Management

Although formatting is the easiest way of fixing corrupted drive, it is not recommended to try it in the first step. When CHKDSK does not work your situation, you may have to try formatting is in Disk Management.

Step 1. Right-click on the Start menu and choose Disk Management option to launch Windows 10 Disk Management.

Step 2. Locate and right-click the partition you want to repair and choose Format option from the context menu.

Step 3. Click OK button on the pop-up windows. Click OK to confirm the action.

Solution 3: Check / repair bad sectors for the external HDD

DiskGenius Free edition offers the function to check bad sectors, and you can run a scanning the disk.

Step 1. Install and launch DiskGenius Free edition and you can see all disks are listed on the left pane. Select the external hard drive you want to fix, choose Disk > Verify Or Repair Bad Sectors.

external hard drive corrupted and unreadable fix

Step 2. Click Start Verify button and DiskGenius starts to verify if the disk contains bad sectors.

During scanning, you can view disk status on the right part, for example, Excellent, Good, Normal, General, etc. Bad sectors are tagged with red blocks, meaning Damaged.

external hard drive corrupted and unreadable fix

Step 3. If any bad sectors found, you can also try repairing them after scanning finishes.

One thing to be noted is that bad sector repairing destroys data instead of recovering data. So, data backup should be performed before repairing bad sectors.

FAQs on corrupted external HDD

1. Why is my external hard drive unreadable?

In most cases, the external hard drive unreadable problem is caused by improper actions, e.g. the external disk gets disconnected from computer before Windows finishes reading or writing actions to the disk. The result is partition turns to RAW and files becomes unreadable.

2. How do I recover a corrupted folder from an external hard drive?

Here are some methods you can try to recover a corrupted folder from external disk:

  • Use data recovery software or retrieve data from backups.
  • Run CHKDSK in command prompt to check and repair errors in file system.
  • Scan for virus and malware.

3. How do I recover a corrupted hard drive without formatting?

The data recovery solutions discussed in this article also works on recovering a corrupted or RAW hard drive. Here is a summary of the recovery process.

Step 1: Download and install DiskGenius on your computer.

Step 2: Open DiskGenius and use File Recovery function to search for lost files.

Step 3: Preview files and copy them to a secure location.

4. How do I fix disk structure is corrupted and unreadable error?

First and foremost, files on the corrupted and unreadable disk should be recovered. After that, you can try following methods to fix it.

Step 1: Install and launch DiskGenius from your computer.

Step 2: Locate the corrupted hard drive in DiskGenius and use File Recovery function to scan the disk.

Step 3: After scanning, you can preview lost files and copy them to a working drive.


So much about external hard drive corrupted and unreadable fixes and hope you can handle it on your own now. A corrupted and unreadable external hard drive can be a scary experience when there are not any backups. Fortunately, the issue can be fixed without losing data: recover lost files prior to repairing corrupted drives. For any questions regarding this issue, feel free to contact us.

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