What are bad sectors and how to cope with them?

February 1, 2018 |

greater than 6 minutes

What are bad sectors?

A bad sector is a sector on a computer disk that is unusable due to either permanent physical damage or reversible software issues. That is a sector on your drive that refuses to respond to read or write requests. A common indicator of the presence of bad sectors is failure or difficulties in booting an operating system. Others include getting messages saying, “Disk can’t be formatted”, and error reports when you attempt to open some files. All disks, which have been in use for a long period, tend to have bad sectors.

Now we classify bad sectors based on the cause or severity of their problems:

Hard bad sectors are also known as physical sectors

They are sectors formed by clusters of the hard drive that are physically damaged. The hard drive head might have touched the rotating plater, and caused damage to that area. Sometimes they are formed when dust or dirt settles on an area of your drive or when your hard disk is exposed to extreme heat. They can also occur due to a general mechanical failure of the moving parts of your hard disk. When your computer experiences a sudden impact while its hard drive is writing data, hard sectors can also be formed.

Solid-state drives (SSD)

They are drives that differ from hard disk drives (HDD) in terms of the absence of moving parts, but they are not immune to bad sectors. Worn out flash cell memory is usually the primary cause of bad sectors for such drives. Hard bad sectors are impossible to repair. As most of these events leading to hard sectors are irreversible, it is fair to say they can only be prevented.

Soft bad sectors are sometimes referred to as logical sectors. They are clusters of storage space on a hard drive that appears to be functioning improperly. An operating system tags a location or space in a drive as a bad sector when it tries to read or write data stored in those areas but realizes that the error connection code does not match the contents of the sector. A computer often understands something is wrong and might mark these sectors as bad sectors, but these sectors are usually repaired by overwriting the disk with zeros.

What causes bad sectors?

Causes of hard bad sectors: Almost all regular factory-produced hard disks have bad sectors identified during the manufacturing process. Modern manufacturing techniques are prone to errors and numerous flaws. Bad sectors lists produced by the factories are called P-Lists, while the G-Lists are composed of bad sectors created by the end user activity on the hard drive.

Even SSDs with no mechanical parts already have bad blocks in them, but these blocks are marked as defective and relocated to the drive’s extra memory cells. Natural wear is the leading cause of bad sectors on such drives. Sectors can only be rewritten so many times and remapped to the SSD’s extra memory before this additional memory runs out. After this additional memory is used up, sectors eventually become unreadable and the drive’s capacity reduces because of this.

There are far more variety of reasons responsible for hard bad sectors than soft bad sectors on a hard drive. In fact, there are so many probable causes with a good number of them unknown. They range from physical damage, old age, manufacturing flaws or errors in the production process to air entering the sealed part of the drive and dust gathering there. Turning off your computer improperly or a sudden power failure might cause the head of a disk to touch its platters. That area becomes damaged, and this results in bad sectors.

Causes of soft bad sectors: Soft bad sectors are a result of software issues (or caused by the operating system itself). When a sudden power failure occurs, it is possible the hard drive shuts down while writing to a sector. In other related scenarios, the hard drive is composed of data that does not match with their corresponding error-correction code. This content or area is then marked as a bad sector.

Virus, malware and similar programs often do various forms of damage to their host system, and the product of these acts at times is a bad sector or multiple ones.

Signs of bad sectors in a drive

The presence of bad sectors could be very costly – loss of data or valuable information. If you have already lost some files to bad sectors, you can recover some if not all of them by using this awesome program depending on the severity of the sectors.

It is pertinent to note that a hard drive working normally does not equate to the absence of bad sectors. Bad sectors simply are not always identified, so a good back up of all your data stored on your drive is generally very important. A few bad sectors in a drive do not necessarily mean the drive is going to fail. On the other hand, if your drive is rapidly creating bad sectors, then it is a bad sign and you must pay attention to this. Regardless, here is a full but not exhaustive list of signs:

  • The drive becomes RAW and inaccessible. Error messages are displayed when you try to access it.
  • You hear strange noises during boot up or when you attempt to access data from the drive.
  • It takes longer than usual to read data or run a program
  • Failure when attempting to format the drive with the quick format option, with the display of error message “Windows was unable to complete the format”.
  • General problems during boot up resulting in a loop or the dreaded blue screen of death.
  • Multiple pop up messages from windows appear, stating a problem has been detected and warning you to back up your data.

Repairing bad sectors

There is no need to panic if you have just confirmed the presence of back sectors on your drive. Windows 10 (and 8 or 7) have a built-in tool or program used for checking your hard drives for bad sectors and fixing them if possible. This tool is known as “chkdsk”. It works by scanning your drive for bad sectors, repairing soft sectors for use again and labeling hard ones as bad or unusable.

Windows, in theory, automatically runs this tool after boot up if it believes there is a problem with your hard drive. Nevertheless, you can also manually make use of it from time to time. Here is a detailed guide on how to do this.

Preventing bad sectors

Like in medicine when prevention of a disease or disorder is far more preferable than curing it, preventing bad sectors is considerably easier and better than trying to repair them. It is also economically cheaper and generally more feasible. This is how you go about preventing bad sectors:

  • Buy quality hardware and related products. Low-quality hard drives tend to have shorter lifespans generally when compared to their superiors, and are far more likely to develop bad sectors.
  • Avoid shaking or bumping your system. Manufacturers are constantly improving the design of drives to make them shock or shake resistant but their efforts fall short of being successful at times. You should take precautions to prevent careless events from occurring. Avoid dropping your laptop to the ground suddenly, excessive vibrations and other physical activities that could cause damage to your hard disk.
  • Prevent abrupt power loss. Do not remove your laptop’s battery while it is still switched on. Do not try to put off your system suddenly through abnormal means. External hard drives should also be disconnected from your system only after you have secured the option of safe hardware removal.
  • Clean your system regularly. By doing this, you can prevent dust or dirt from settling on almost all parts. Thus, it becomes very unlikely that dust gets into the internals of your hard drive to cause bad sectors.
  • Keep your system away from extreme heat. Extreme heat and a host of other physical factors can do damage to your computer’s hard drive. Proper ventilation prevents your system from overheating.
  • Maintain good software hygiene. This is probably an underrated precaution but it is actually the most important tip. Soft bad sectors are easily preventable by adhering to these instructions:

First, ensure you are running a powerful antivirus along with proven antimalware software to guarantee the security of your system.

Second, use an excellent tool like Disk Defrag to defragment files regularly on your hard drive. It is a trusted software on the tech community for optimizing file placements. It makes free space available to ensure the highest data transfer speeds involving your hard drive.

Defragmentation causes your hard drive to do unnecessary hard work, which causes it to wear out and results in a shorter life span than expected. End this process now by defragmenting your disk with the software above to increase the life span of your drive and even get a boost in performance as a bonus.

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