How To Fix Bad Sectors On A Hard Drive

Let’s KISS…. (keep it stupid simple)

What is a bad sector on a hard disk?

The best data recovery company to work with, is one that can keep it simple and explain in layman’s terms. Sectors on a hard drive are sections of the platter where data is written and read from.

You can think of sectors, or blocks of a hard drive as a small containers within a much larger one. Once they are broken/damaged, they cannot be used again. When it comes to recovering files from hard drive failures like this, even the best recovery service cannot fix these. They are not repairable, but can only be avoided during the process of reading or writing to the drive.

Depending on the size of the hard drive it can contain hundreds of millions of sectors where data will be written to. Each sector is usually 512 bytes. However in modern drives the sector size has been enlarged to 4096 bytes, generally referred to as 4K sectors.

How many bad sectors are acceptable? Well, consider a regular size picture taken from the camera these days, there may be 2 MB, which equals 2 million bytes that make up that picture.

Where the bad sectors are located, will initially determine how they affect the function and health of the drive.

Also, you can’t see bad sectors, or bad blocks on hard drive without special equipment. They are not visible on the platters. In this bad sector recovery image the brown boxes show bad sectors, or sectors with read problems as opposed to the green boxes that are healthy.


What do you mean new hard drives come with Bad Sectors?

What causes bad sectors? When the sector goes bad on a hard drive it will not be be able to be read or write to it.

Bad sectors also cannot be repaired. There is no software that can fix or repair bad sectors on a hard drive.

Believe it or not, most hard drives come from the manufacturer with bad sectors.

The difference is there are measures in place to deal with this.

When a hard drive realizes there’s a bad sector, it usually rewrites the address of that particular sector, and re-routes it on the fly to another sector on the drive that is good.

Kind of like a detour in a road.

The hard drive also adds this to a list called the G list. When defects, or bad sectors, from the manufacturer and are realized during the manufacturing of the hard drive, these also go into a list called the P list.

Why you need data recovery when your hard drive has bad sectors.

A few bad blocks  on your hard drive
can cause a host of problems:bad-sectors

  • Unbootable drive
  • Corrupt partitions
  • Corrupt files and directories
  • Corrupt firmware
  • Unusual wear and tear on the drive

When a hard drive has bad sectors it may still be recognized by a computer. Most of the time the drive will not boot or at least the files will not be accessible.

The hard drive will run slow, and tend to hang during certain times of operation especially during initialization and operating system startup.

A few bad sectors on drive should not be problematic, but when they are in the wrong place or in abundance, it’s time to backup your data in order to avoid needing data recovery services.

How can you recover data from a hard drive with bad sectors?

Past a certain point, you can’t without special equipment.

Computer repair companies and IT companies do not have the equipment necessary to overcome bad sectors. The most they can do is run software, and say they can do hard drive bad sector repair, which poses another problem.

When running software on a hard drive that is failing due to bad sectors, the software will tend to hang on a bad sector and try to reread it multiple times even to the point where it will not be able to move on passed that sector.

This can cause more damage to the drive and even bring it to a state where it is not able to be recovered even by a professional data recovery service.


Does a hard drive with bad sectors require advanced level data recovery?

In short yes.

However, data recovery companies have special hardware that is able to overcome bad sectors. This is because the read time that a head will take to try to read an individual sector before skipping it can be adjusted.

These devices are called hardware level imagers.

These are very advanced data recovery tools that are very versatile and easy on the drive to prevent further damage. This makes our job easier.

When these special tools are not used to clone the drive that has bad sectors, the condition of the drive is at risk especially the read/write heads in the motor.

At SERT data recovery we consider this type of recovery a basic level recovery. Because we have the right equipment and experience, we are able to easily overcome hard drives with bad sectors and successfully recover data.