▷ How to erase a hard drive completely

In this article we are going to teach you how to erase a hard drive safely and without the need to be an advanced user of computing. In the event that you decide to throw your hard drive in the trash, sell it to another user or simply save it in a drawer, but in no way enabling the recovery of your data. You want to know more? Do not miss our tutorial!

Many people do not know, but when we delete a file from the computer, it is not really deleted. The operating system simply removes it from the list of files on the disk and frees up the space it was occupying before for use. In other words, the operating system does not fill that space, that is, it does not clean the space that the file was previously occupying.

Unfortunately, this is one detail that doesn't get the attention it deserves: secure erasure of the hard drives you're about to sell, give away, or throw away. If you think about it, your digital life has passed on your disk, and if this data ends up in the wrong hands, your security may be at risk.

So if you decide to sell or give away your old hard drive (or directly your computer), our advice, once you are sure that you have imported all your data, is to erase them safely.

The same advice also applies if you're returning your company's laptop (to get a new one in return). It is true that a worthy IT administrator should recondition the system and / or safely delete everything, but if this is not the case, this guide is recommended reading.

Especially on modern hard drives, where capacity is now measured in terabytes, it is not certain that the freed space will be used immediately. Any data recovery software could easily recover your private information, even if you deleted it months ago.

Beyond that, even if you do not sell your laptop, it is recommended that you do a data cleaning to maintain the good performance of your computer. When a virus or any other type of malware attacks your system, erasing the data is always a good idea. Take a look below at the situations when it is useful to erase data from a hard drive:

• Sometimes when a large amount of data accumulates on your computer, its performance suffers from that and it is too slow. Clearing the data makes the performance of the computer faster. When a virus affects your computer, your only option is to erase the data, that is, formatting. This is going to leave the hard drive looking like new. To keep your hard drive in good condition, you need to clean it regularly. This will prevent fragmentation and many other problems. If you intend to join or create a new partition, it may be necessary to delete an existing partition on your computer. To do this you will have to do a total cleanup of the disk. If you want to install a new operating system on your hard drive, you will have to clean the old operating system, and only after that install the new one. Therefore, you will have to erase the old data on the hard drive to continue with the new installation.

Index of contents

An erase that is not a complete erase

The operating system deletes data in this way to save time. Imagine a large file, occupying several sectors of the disk. In order to actually delete this file from disk, the operating system should pad all sectors occupied by this file with zeros (or any other value).

This could take a long time. Instead, it simply removes the name of the file from the directory where it is located and marks that the sectors previously occupied by the file are now available.

This means that it is possible to recover a deleted file, since the data of the deleted file has not been deleted from the disk. So deleted file recovery programs work. And although the area occupied by one file overlaps with the data from other files, the area around the sector, being magnetic, can continue to store portions of the original data, and through special data recovery equipment, in In some cases it is possible to recover the original data, particularly on older hard drives (on newer hard drives, with increasingly smaller sectors, the probability of magnetic charges around the data sector is less).

This fact generates a major security problem: if you have really confidential files, which cannot be discovered in any way, deleting them from the disk simply by pressing the "Delete" key and then removing it from the Recycle Bin will not prevent it from being discovered by using of advanced data recovery utilities.

Data overwriting, the right method

It may sound silly, but the safest way to erase a HDD or hard drive safely is by overwriting data. And in this guide we explain step by step how to do it. You will see that safely deleting a hard disk drive is a procedure available to everyone. It is true that it takes time, but it is a process that, once started, can continue automatically.

There are many solutions on the market, free or not, that work within the operating system or outside. One of the most recommended methods is to use DBAN (Darik's Boot and Nuke), a rustic program, but one that does its job very well.

Format a hard drive

The format of a disc is no different. When we format a hard drive, either through the operating system installation menu or through the Format command, the data that was previously present is not erased, allowing an advanced data recovery utility to recover files even after formatting the hard drive.

Many people who have a hard disk with confidential files think that formatting the disk will delete all the data and there will be no possibility of recovering the files. This, however, is far from true.

This is the only difference between the "fast" format (without disk verification) and the "full" format (with verification). In other words, in the same way that happens when we delete files, the hard disk is not really overwritten when we format it.

Finally, even when everything is formatted and a new operating system is reinstalled, it is not certain that the old data is no longer recoverable. Although some portions of the disk are rewritten, data recovery software can recover files, even in the case of partial rewriting.

The most extreme and rudimentary method

The ideal process to eradicate the probability of recovery of any type of data from a hard disk is to demagnetize the magnetic disks and then destroy the hard disk using a specific shredder for this purpose.

If you dispose of an old computer after buying a new one, you could simply destroy the hard drive that you will no longer use. Nailing a few large nails through the drive at specific points is a great way to ensure that the drive is completely useless and that your data is safe.

Watching the Mr. Robot series, our friend Elliot decides to drill the hard drives of his PC before doing it with hammer blows, burning them or throwing them out the window. It is undoubtedly the best way to render a hard drive unusable.

Software to erase a hard drive

In the case of wanting to continue using the hard disk, you can use a program to fill all sectors with zeros, since this process needs to be done several times and with different values ​​being written in the sectors in each pass, because, as we have explained, the magnetic charges around the sectors can continue to store fragments of the original file.

Hard drive manufacturers generally provide this functionality through the utilities available on their websites, also known as "low-level formatters." In the case of Seagate, the program is called DiscWizard and offers secure erase of the hard disk (that is, several passes with different values ​​in each one).

In the case of Western Digital, the program is called Data Lifeguard, and it only writes zeros, being less secure than the Seagate program. The DBAN program also only writes zeros, but the developer also offers a paid version that does the secure erase.

Padding the hard drive with zeros is enough to prevent data from being retrieved with data recovery programs (99.99% goal for common users), but to prevent it from being retrieved through special equipment that reads loads magnetic around sectors, a secure erase program is required, that is, it seals all sectors of the hard disk with different values ​​in each pass.

Eraser

It is a utility that can be programmed to periodically rewrite empty spaces and track orphaned files.

There are several programs for secure file deletion, and one of them is Eraser, which allows random data to be written multiple times over the area occupied by a sensitive file that you really want to delete.

It is important that the new data is written multiple times so that the magnetic areas around the sectors that store the fragments of the original files are also removed, so that data recovery is impossible, even with the use of special equipment.

The use of this program makes it impossible to recover the sensitive file or any part of the data contained in the deleted file.

DBAN

DBAN works by systematically replacing all the data on your hard drive with a random sequence of data. This completely destroys the old data on your drive and it is almost impossible to recover it.

You can use DBAN in several different ways, but the "autonuke" method is the easiest. Autonuke is a three pass wipe that results in the destruction of your data to a DoD standard (the method used by the United States Department of Defense).

Download the DBAN ISO file from their website and then create a bootable USB stick. Start your machine using this USB memory, and in the main command line enter the command "autonuke" and press the "Enter" key.

DBAN will then automatically start cleaning the drive, performing three passes to overwrite your data three times. This process can take many hours to complete depending on the size of your hard drive, so it is probably best to leave the process running overnight.

Once all three passes have been completed, the data on your drive will be completely erased and unrecoverable. You can then reinstall the operating system if necessary.

As mentioned, DBAN is free software. The download file is an ISO, with which you can create a bootable CD or, more simply, a bootable USB stick.

The advantage of a solution like DBAN that starts as a boot system is that it can be used directly on the system to do a cleanup; otherwise, you would have to unmount the disk and connect it to another system (a feasible solution with a PC, but much more complex than doing with a laptop).

You will have to select the correct disk whose data you want to erase (choose the correct disk, because once the process starts, there is no way to recover anything). Set the number of write and erase passes. With three passes, everything will be erased.

Depending on the cancellation mode you have chosen, the required time can vary between tens of minutes and tens of hours. If you don't have supercritical data or are not a government organization, the default setting (DoD Short) is more than enough to erase your disk, without compromising your equipment too much.

Disk wipe

Another good free app is Disk Wipe. The only downside is that it is a Windows application, so you have to run it from an existing operating system, while DBAN can be started using a CD or flash memory. And since it is a Windows application, you can actually only erase Windows formatted hard drives (NTFS, FAT32, FAT or other).

However, if that's not a problem for you, then the show is great. It is portable and does not require any installation, so you can take it on a USB memory or simply send it by email. You can erase hard drives, memories, SD cards and much more.

It also supports advanced algorithms like DoD 5220-22.M, US Army, and Peter Guttman.

Windows Utilities

• Microsoft SDelete: Safely delete files and directories, or clean empty spaces. Wipe File: Rewrite the space left by the deleted file. DeleteOnClick: This utility has a “Secure Delete” function based on the DoD 5220.22-M standard of the Department. of Defense of the United States, which rewrites files securely.

Mac OS X Utilities

• Permanent Eraser: to be used instead of the Empty Recycle Bin option in safe mode. Rewrite 35 times to disk. Disk Utility: This utility comes standard on Mac OS X. It has a "Clear Free Space" function that can rewrite in areas left empty 1, 7 or 35 times.srm: is the command used in a Terminal application console to delete or overwrite files. Old data cannot be recovered.

Utilities under Linux (Ubuntu)

Wipe application in Ubuntu Unleashed: deletes files safely after successive rewrites, even works best on entire folders.

Using hardware

If you want to fully automate the process and the software is not your thing, you can always go for a hard drive eraser. They are not cheap, but they are very useful, especially if you have multiple drives to erase.

They are faster and means you do not have to dedicate a PC to the cleaning operation.

Draft HDD drives

Devices like Startech Drive Eraser and WiebeTech Drive eRazer Ultra are great and make the process of erasing your data a breeze. Just dock the unit and press a button; the eraser will do the rest.

Most of these storage drive erasers also allow you to print the erasure results.

The Drive eRazer Ultra from Wiebetech. It is a fast, reliable and autonomous solution to clean hard drives and eliminate everything. Connect the unit to this dock, press a few buttons and Drive eRazer Ultra will take care of the rest. It is an expensive solution, but it offers security.

If you have a lot of drives to erase, you may want to look for a tool that can erase multiple drives simultaneously, like the StarTech Four-Bay HDD Eraser.

This eraser of four bay hard drives from StarTech includes the following features:

• Secure and standalone erase of up to four 2.5-inch and 3.5-inch SATA SSD / HDDs. Nine erase modes including: fast and secure erase, single-pass overwrite, and multi-pass overwrite - Meets the DoD (5220.22-M). Secure Erase and Enhanced Secure support for SSDs. Easy handling thanks to LCD screen and navigation buttons. Built-in nine-pin serial port allows printing of erase records using a receipt printer. SATA support I and II (up to 3 Gbps). Also supports 2.5 and 3.5-inch IDE hard drives, mSATA drives, and M.2 SATA drives using a compatible StarTech.com adapter. Complies with TAA (Trade Agreetments Act).Plug-and-play installation.

The hard drive eraser is easy to use, thanks to its convenient menu navigation system, with button operation and an integrated LCD screen that clearly identifies erase modes and task status. You can also connect the eraser to a computer for quick access to the unit that is connected to port 1 of the eraser.

Do a full encryption of the hard drive

Full disk encryption is not really a way to erase data from your hard drive. But it's a great way to ensure that your data can't be read, even if you only format the hard drive when it's time to get rid of it.

Encryption works by encoding all the data on the drive using extremely complex math. Encrypting a drive makes it almost impossible for curious people to access your data, thus virtually eliminating the need to erase it.

If you are unlucky enough to inadvertently sell your computer to a hacker, having an encrypted drive will mean that unless the hacker is directly a crack, your data will be safe.

On your next PC purchase (especially if you're considering buying a laptop), consider encrypting your hard drive first with software like FreeOTFE or TrueCrypt.

You will have to create a password (which will be requested when you start the computer) complex enough so that it cannot be guessed and found by potential thieves.

Therefore, when your computer needs to be replaced, you will not have to physically destroy its hard drive.

Conclusion on how to erase a hard drive

Computer security is everyone's responsibility. Because many of us turn to computers for online banking, budgeting, or even using social media, it is more important than ever to ensure that the data we share with people is limited. Even if you share it by accident.

We recommend reading the following articles:

• Best SSD on the market

Surely you would not give the password of your PC to a stranger, so do not give all your personal data stored on the hard drive for lack of diligence. If you are selling or removing an old machine, make sure your data is completely destroyed.