There are several symptoms that you can start to suffer on your PC when your hard drive has bad sectors: from extreme slowness in processing files stored on the hard drive to strange noises in the drive, through crashes and file corruption. If you start to notice any of these symptoms, it is possible that your hard drive is starting to die from too many bad sectors, but don’t worry because there is still a chance to repair them to bring the drive back to relative normality.
What are bad sectors and why do they occur?
Internally and in order to better manage information, mechanical hard drives group the information they hold in sectors made up of a certain number of bits. These sectors are created so that, we repeat that internally, a kind of map or index can be created so that the disk knows where each bit of information is housed and is able to send the moving head to the appropriate sector to be able to read or write the information .
When you try to read or write to a sector and, for whatever reason, the head is not capable of it, the drive reports it as faulty and discards it (this means that the next few times it will not even try to read or write to that sector ). There are two types of bad sectors and the causes that produce them are multiple, but we will try to explain it in the simplest way possible:
- Physical problems: generally caused by impacts (dropping your hard drive to the ground, for example) or serious errors with the head (known as head crash) in which the platter has been physically damaged and, therefore, certain sectors have been left permanently inaccessible. This type of bad sector cannot be repaired, although we can mitigate the problem by having the hard disk permanently discard the affected sectors to avoid errors.
- Logical problems: They are caused by a failure in the reading or writing of the disk, which can be caused for example by a sudden power failure while the hard disk was writing data. In some cases they can also be caused by errors or data corruption in which the sector has disappeared from the index that we talked about a moment ago. In these cases, the problems can be fully repaired.
How to tell if your hard drive has bad sectors
In the image that we have placed above these lines you can see the inside of a hard disk that has suffered a “head crash”, and in which it is clearly seen that the head has completely damaged the surface of the platter, rendering it practically unusable. If this is your case, you will notice that the hard disk makes a series of strange noises, such as scratching or scraping, and obviously it is not working correctly.
To find out if your hard drive has bad sectors, the best thing you can do is use the tools that Windows contains for it, since they are simple to use and really very effective. We talk about the utility CHKDSK We have already talked about it on previous occasions, a tool that is precisely designed to detect and repair almost any type of problem that you may have in your storage units (not only hard drives but also SSDs or even USB Flash drives).
To do this, right-click on the Start button and select the “Command Prompt (administrator)” option. In the window that opens, you must execute (type and then press ENTER) the following command:
chkdsk x: / F (where x is the drive letter assigned to the hard disk; you can check its handwriting simply by going to “This computer” in Windows).
If you are executing the command directly from Windows, you will see a screen similar to the one above, in which the operating system tells us that the unit is in use and that it cannot be analyzed, urging us to unmount the volume (something that only It will appear in the event that the hard drive to be analyzed is not where you have the operating system installed) or if you restart the computer and that CHKDSK runs automatically on the next boot. Either way, hit the Y on your keyboard and then ENTER to accept.
The process consists of three phases, in which the system will first analyze the drive and then try to repair any errors it finds (the third phase is simply verification). The process can take a long time depending on the capacity of your hard drive and the number of errors it finds, but if the errors are fixable, this tool will take care of everything and you will not have to do anything.
Another way to check if your hard drive has bad sectors is also built into Windows. Go to “This computer”, right-click on the problem drive and click on “Properties”. There go to the Tools tab and you will see something like this:
Click on the Check button, and the system will analyze the hard drive for problems, errors and bad sectors. In the event that it finds a problem, the software itself will suggest that you try to repair it automatically without you having to do anything else.
Can bad sectors on hard drive be repaired?
As we have mentioned, both with CHKDSK and with the Windows Check tool you can detect and try to repair bad sectors on your hard drive, but neither of these tools is completely infallible (and the problem may not be repaired if the damage is physical , as we told you at the beginning) so the hard drive may not be in good condition despite everything.
If the problems are not physical but logical and the previous tools have not been able to solve the problem, another more direct method is to perform a low level formatting of unity, a process that will delete all information It contains (so back up the data first) because it literally resets all the bits on the hard drive one by one, including the sector assignment and index.
This is a pretty radical way to repair a hard drive with bad sectors, but if the bad sector problems are not repairable they will be skipped in the new sector assignment and therefore you can continue to use the hard drive after the process. Of course, if the amount of bad sectors on the disk is large enough, you will see that its maximum capacity will have been reduced since, literally, it will have fewer usable sectors.