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    Technology Manager of Test Dept.

Bad sector will occur after using the hard disk for a long time. Here we will go through some related knowledge about bad sector and get professional free methods to detect and repair bad sectors in HDD.

To get a competitive price, parts of personal computer still uses HDD to save data. And parts of computer may use SSD to be the system disk. Here we will focus on how to repair bad sectors in HDD.

1. What is Bad Sector?

Sectors which is either inaccessible or unwriteable are called bad sector. Bad sectors could be caused by permanent damage like physical damage, failed flash memory transistors.
disk illustrator
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2. What does Bad Sector Bring?

1. Loading time of files will be longer.

2. Users can hear some noise when disk running and Windows may notifies users that the file is inaccessible.

3. Disk can not boot. Users could find the drive letter of the disk but can not make any changes. Some even could not find the drive letter.

4. Repeat to access the files when users want to access it. And notifies the file is corrupted. Or take a long time to access the file

5. System can not boot as usual and pop up notification like “Sector not found” or “General error in reading drive C”

6. Can not format the disk and report error

7. Run Scandisk to find disk error automatically every time user start the PC

8. Windows notifies that “Windows detected a hard drive problem”

windows detect a disk problem
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3. How to Deal with Hard drive with Bad Sector?

Bad sectors could be divided into soft bad sector and physical bad sector.
Soft bad sector: Also called to be logical bad sector. The weakening or unstable magnetic areas or some improper operations could caused the ECC (error-correcting code) does not match the content of the sectors.

Physical bad sector: The hard drive’s head may fail to read data in the disk. Or the reading time is longer than before. If users keep using the disk with physical bad sectors, sectors near the physical bad sector will fail to work generally.

However, we can not figure out which bad sector we have meet. But we can find the real reason with correct disk repair steps.
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4. Process of Repairing Bad Sectors in Windows 10/8/7?

Step 1: Get more information about how many bad sectors in the hard drive with bad sector detection tools.

Here, we recommend the free detection tool: HDD-SCAN (Click here to download the software)。


AS we can see in the scan result, lots of bad sectors are found when the scan process to 78%.

windows 10 slow startup bad sector found in HDD Scan

Besides, HDD-SCAN can export the scan result with detailed information of the bad sectors.

export detection result in HDD Scan

Step 2: Contact with the HDD manufacturer and get the repair tools to repair bad sectors.

Attention: Using the repair tool provided by the disk manufacturer could erase all data inside the disk. If you do not want to lose data inside, please backup data inside beforehand or use the built-in disk scan tool in Windows.

Seagate & Maxtor

1. Download and install SealTools.

Please do not download the SeaTools which is for Windows. Because that version only support to scan and repair disk from not serious problem. If you want to fix bad sector, please download SeaTools (DOS version). Download Now.
sealtools for Windows

2. Please burn the iso file to disc with freeware ImgBurn.(Download ImgBurn

burn the file with ImgBurn

3. Please boot the computer from the disc after burning. Please select “Basic” -> “Long Test” to find and fix bad sectors.

Boot from the burned media

West Digital

This software is developed to detect and fix the error in disk manufactured by West Digital. (Download West Digital Now).
After installation, please double-click the disk icon for further operation.
Data Lifeguard Diagnostic

Built-in Disk Repair Tools in Windows 10/8/7

If you could not find the related disk repair software from your disk manufacturers, you can fix the bad sectors with the built-in disk repair tool Windows 10/8/7.

1. Press Win + R button and type “diskmgmt.msc” in the pop-up window. Click “OK”.

enter diskmgmt.msc in run

2. Right click the target partition in the disk and select “Properties” in the menu.

properties of disk

3. Click “Check now” button in “Tools” tab.

run check to find erros in storage device

4. Remember to check the item “Scan for and attempt recovery of bad sectors” in the pop up window if you are using Windows 7/8.

check disk
Error-checking will mark the bad sectors so they won’t be used again. If you scan the disk for bad sectors with HDD-Scan, they will be detected.
If you want to fix this problem, low level format is the only choice, which could not solve this problem sometimes. Or you can replace the hard drive.

Step 3: If there are still lots of bad sectors after fix or they get corrupted again, we should purchase a new hard drive.

To replace a new disk, you need to transfer data in the original hard drive to the new one. We recommend you to try freeware – Renee Becca. This software can copy and transfer data from one disk which may has bad sectors to another. You can also only migrate system to the new disk with Renee Becca.

download button win

Only a few steps you can transfer all data to the new disk.
select hard disk clone function
clone to disk with larger size

More Functions in Renee Becca

New version of Renee Becca can clone entire HDD to SSD with smaller size.

Support to set automatically backup plan and more customized backup options are provided in the software.

Support to clone/migrate data in disk with MBR or GPT format.

New disk could be used to boot the computer once clone finish.

Support to migrate system from HDD to SSD.

Compatible with Windows 10 / 8.1 / 8 / 7 / Vista / XP/2008/2012 (32bit/64bit) / server 2008

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5. Low Level Format

Low level format will erase all information in the disk and factory reset whole disk. Low level format will skip some areas which is unstable or can not save data. As a result, Windows or HDD-Scan will not be able to save data or access to these areas.
Low level format will have negative influence to the life span of the hard drive. So, please do not make this operation unless it is necessary.
We recommend you to make the low level format with HDD LLF Low Level Format Tool. Please download the software:
how to format sd card with HDD LLF Low Level Format Tool
format disk with HDD LLF Low Level Format Tool
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6. Fix 0 Cylinder Error

Situation Analysis

Once users encounter this situation, PC can not boot as usual. And “No bootable device” will be shown. And you may receive the information like “Disk is not effective or 0 Cylinder Damaged” when you try to format the disk in other systems.
No bootable device notification
This problem could be caused by the 0 Cylinder error. And users can not write data or access to the disk. This 0 Cylinder is quite important and the process of solving this problem will be complicated.

Without the 0 Cylinder, computer can not boot as usual and fails to partition and format.


0 Cylinder damage will lead to the lost of partition table. And we can not fix or isolate the bad sector with chkdsk, HDD-Scan or built-in disk scan tool in Windows.

We can find back important data from the disk with data recovery software which is equipped with partition table rebuild function. Then we can make the 1 cylinder to be the 0 cylinder with special third party tools.

Step 1: Take off the hard drive and connect it to another computer which can work normally.

If you connect the disk with USB hard drive enclosure to another computer, please choose an enclosure with good quality. Because the following operations may take hours even days.
connect disk to PC with dock station

Step 2: Please recover important data from the disk with data recovery software which is equipped with partition table rebuilt function.

Because this scan mode will scan whole disk with a great deal of arithmetic. So the scan and recovery will take a long time.
Here we recommend professional data recovery – Renee Undeleter could do you a favor. “Whole Disk Scan” in Renee Undeleter will rebuilt the partition table and regain access to all files (including the deleted files) inside the partition without MBR information.

download button win4

select whole partition scan in Renee Undeleter
scan disk with whole disk scan of Renee Undeleter

Professional Data Recovery Software - Renee Undeleter

Supports to recover files in different formats, like photos, videos, music, Office files, Outlook email, software installer, etc.

Compatible with Windows 10, 8.1, 8, 7, Vista, XP, Mac OS X 10.6 and later versions.

100% Safe. Scanning disk with Renee Undeleter will not damage or delete any files or data inside hte target disk.

Preview before recovery. Users can preview the scanned files when scanning process. Once you find out the target files, you can stop the scan and process the recovery.

Easy to go software interface.

Step 3: Fix the 0 Cylinder with PCTOOLS or Disk Manager.

Here we recommend users to fix the disk with Disk Manager from IBM.
1. Press “ALT + M” to access to Advanced Management Mode
2. Click “Edit/ViewParations” menu (Top-right of the screen will show the disk settings in BIOS).
3. Press “Del” or “Delete” to delete all partitions. And press“Insert” or “Ins” to build a new partition and choose the partition format (FAT12, FAT16, FAT32, etc) according to your needs. 
4. Go to “Cylinder” and change the 0 in “0, XXX” to be “1”, which will make the 1 Cylinder to be the 0 Cylinder.

Please note that XXX here means the ending cylinder of the partition and please modify the value according to your need.

5. Save the settings and then format the disk.
Please do not save important data to this disk even recover the disk successfully. Besides, please check the disk and replace with a new disk as soon as possible once you encounter bad sector. Here, we recommend you to try professional free data backup software -  Renee Becca.
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