How to Fix Bad Sectors on External Hard Drive: Windows Instruction

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fix bad sectors on external hard driveBad sectors aren’t a good look on any hard drive. If some bad sectors have started to appear on your external hard drive, they may be revealing a problem that could get worse with time. But, what are they exactly? Are they something you can ignore, or are they an early warning sign of your external hard drive’s upcoming demise?

In this article, we’ll explain what they are and how you can fix bad sectors on an external hard drive.

What Are Bad Sectors on a Hard Drive

Every hard drive contains spinning magnetic disks that store your data. Each disk is divided using sectors. Bad sectors are parts of a disk that are no longer usable due to it being permanently damaged. When a bad sector appears, there’s a good chance the data is lost, depending on the type of bad sector it is. Operating systems, like Windows, will automatically mark the sector as unavailable so no data is written to it going forward.

It’s normal for hard drives to have a few bad sectors, but once a disk starts to accrue a large number of bad sectors, it generally points towards disk failure.

How to check bad sectors of drive
Method Instruction
Command Prompt Open cmd, type chkdsk X: (where X is the drive letter you want to check).
File Explorer Open “This PC” tab in File Explorer, right-click the drive and open Properties. In Tools tab select “Check”.

What Causes Bad Sectors on a Hard Drive

Hard drive bad sectors come in two varieties: physical and logical.

  • A physical bad sector is the result of physical damage, such as the hard drive head making contact with the disk or overheating issues.
  • A logical bad sector can be caused by software, malware, and interrupted disk write processes.

Physical bad sectors cannot be repaired. Moreover, you cannot recover data from them. Instead, they’re marked as unusable, and the data residing in that sector is lost. However, logical bad sectors do have a chance of being repaired using repair tools. We’ll demonstrate how in the next section.

How to Fix Bad Sectors on a Hard Drive

Fixing an external hard drive with bad sectors has no guarantee of success. But, there are some fixes you can attempt to implement in hopes to restore it to working condition. Here are some solutions that will show you how to fix bad sectors on an external hard drive.

Solution #1: Repair Using Troubleshooters

Windows comes with a host of troubleshooters that are designed to find and resolve problems with your computer. The troubleshooter we’re going to use this time is the Hardware and Devices troubleshooter.

Try these steps to repair the external hard drive using a troubleshooter:

  1. Right-click Start and select Windows PowerShell (Admin).Opening Windows PowerShell.
  2. Type msdt.exe /id DeviceDiagnostic and press Enter.Running the msdt.exe command to open the troubleshooter.
  3. Click Advanced and ensure Apply repairs automatically is ticked. Click Next to let the troubleshooter start scanning.Running the hardware troubleshooter.

Solution #2: Repair with CheckDisk

CheckDisk is a Windows repair tool that can repair bad sectors on external hard drives. It’s able to scan your drive for logical and physical errors. It maps out unusable physical bad sectors and attempts to repair logical ones.

The below instructions will guide you through using CHKDSK on an external drive:

  1. Right-click Start and select Windows PowerShell (Admin).Opening Windows PowerShell.
  2. Type chkdsk D: /f /r. Replace D: with the drive letter used by your connected external hard drive. Press Enter.Running the CheckDisk command.

Solution #3: Repair with Repair-Volume

CheckDisk is a very useful command, but sometimes it misses the mark. The repair-volume command was released with Windows 8 and Server 2012. It is similar to CheckDisk, with the benefit of added functionality. It can find and repair volume-related problems, such as bad sectors.

Here’s how you can use the repair-volume command to repair a hard drive with bad sectors:

  1. Right-click Start and select Windows PowerShell (Admin).Opening Windows PowerShell.
  2. Type Repair-Volume -DriveLetter D -OfflineScanAndFix. Replace D with your own drive letter. This will take the drive offline momentarily to try and fix it. Press Enter.Running the repair-volume command.

Solution #4: Perform a Full Format

One of the most reliable ways to fix hard drive-related problems is by performing a format. In most cases, you can get away with a quick format to fix external hard drive errors. But, when it comes to the case of bad sectors, you need to perform a full format instead. A full format will scan every part of the drive for bad sectors. Bad sectors are then remapped to backup sectors so the problematic sector is no longer used.

  1. Right-click Start and select Disk Management.Opening Disk Management.
  2. Right-click your external hard drive’s partition, then select Format.Formatting the external hard drive partition.
  3. Specify the name and file system you want to use. Make sure Perform a quick format is unticked. Click OK.Defining the format parameters.
  4. Click OK when asked if you want to continue.

How to Recover Lost or Deleted Files From an External Hard Drive

After you fix bad blocks on a hard drive, either through formatting or using one of the other proposed solutions, most of the time you will face some level of data loss as a result. While some data may be lost forever due to the inflicted damage, you can try to recover any data that remains using a data recovery tool, like Disk Drill, to find and recover the data that’s missing. Disk Drill isn’t able to repair the external hard drive, but it is capable of scanning it and restoring data that was thought to be lost or deleted.

Performing recovery on an external hard drive that has faced data loss can be risky, as any mistake can cause the data to become unrecoverable. Therefore, these instructions will guide you through making a byte-to-byte copy of your external hard drive and recovering data from it:

  1. Download Disk Drill to your computer and open it.
  2. Click Drive Backup. Select your external hard drive, then click Byte-to-byte Backup.Selecting the external hard drive to back up.
  3. Give the backup a name and specify where you want to store it. Click OK. Click Done when it’s finished.Starting the byte-to-byte backup.
  4. Go back to the Data Recovery section, and attach the disk image by clicking Attach disk image.Attaching the recently created backup.
  5. Select the disk image and click Search for lost data.Searching the backup for lost data.
  6. Click Review found items.Reviewing the data that Disk Drill discovered.
  7. Search the results and tick the files you want to recover. Using the Recovery chances column, you can get an idea of which files have the best chance of recovery. Click Recover when you’re ready.Recovering the marked files in Disk Drill.
  8. Select a destination to save them. Don’t choose a location on the same external hard drive you’re recovering from. Click OK to finalize.Finalizing the recovery process.


On Windows 7, you can remove bad sectors from a hard disk using the error-checking tool.
  1. Click Start, then click Computer.
  2. Right-click the hard drive, then select Properties.
  3. Click the Tools tab, then click Check now under the Error-checking section.
  4. Check Automatically fix file system errors and Scan for and attempt recovery of bad sectors. Click Start.
  5. Click Force a dismount.
Fixing bad sectors on a hard drive is possible, but it depends on the type of bad sector. If it’s a logical bad sector, otherwise known as a soft bad sector, there’s a chance of fixing it. However, if it’s a physical bad sector, also known as a hard bad sector, the sector cannot be fixed. Instead, it is marked as unavailable so your operating system no longer stores data there.
It’s easy to scan and repair a damaged sector on a hard drive using CheckDisk, a repair tool included with Windows. Follow these steps to do so:
  1. Right-click Start and select Windows PowerShell (Admin).
  2. Type chkdsk D: /f /r (replacing D: with your drive letter) and press Enter.