Let's think for a moment about all the sensitive data saved on the computer: passwords, addresses, telephone numbers, access to bank accounts and other financial services, photos and so on. Almost all aspects of privacy are inevitably kept on the hard disk or SSD inside the computer. If we change the machine, maybe we don't think for a moment about all the data contained inside and we run the risk that someone else may access the data stored on the disk.
It's not to be paranoid but information thieves are always looking for personal data stored on old computer disks.
If we really want to empty the hard disk from any data and prevent our files from being recovered, in this guide we will show you how to format a hard disk or an SSD to erase everything permanently, so that we can reuse a drive on another computer or even resell.
For the new SSDs, there are a few small tricks that we will show you to avoid damaging the drives.
READ ALSO: How to format a disk in Windows 10
1) Quick format hard disk
If the disk in question is to be reused on our machines (so it doesn't leave the house), we can format it quickly without wasting too much time using the formatting tool available inside Windows.We connect the disk to be formatted as a secondary on our PC (both using another SATA port and connecting it as an external USB disk), start Windows and go inside File Explorer or Windows Explorer .
Open this window we open This PC or My Computer, we identify the secondary disk connected a little while ago (we can get help from the capacity and any files already present), we right click on its icon and finally we click on Format .
A new window will now appear where you can choose the file system to use (we recommend NTFS ) and where to check the Quick format item; as soon as we are ready, click on the Start button.
Using quick format the disk will be immediately available and will appear as blank to any operating system; however, it only deletes the boot sector and the partition table, leaving all other files intact and accessible through specialized software. It is therefore not the best procedure if we have to sell or give the disk or the whole PC to someone else, since the files can be easily recovered.
2) Erase all data from a disk permanently
On a disk connected to the PC or secondary, you can use the format mode to completely erase the data.In Windows 10, open Powershell from the Start menu (with Run as administrator mode) and then type the following command:
Format X: / P: 5
Instead of X, put the identification letter of the disk to be erased.
3) Advanced hard disk formatting
To eliminate all data without the possibility of recovery we can use an external program that does low-level formatting, also called " disk reinitialization "; this process sets all binary values to zero and erases a hard drive completely .
HDD Low Level Format Tool
The best free program we can use to format a hard drive is definitely HDD LLF Low Level Format Tool.
To use it, simply connect the disk to be formatted as secondary on our PC (USB or on another SATA connector), open the program and select the correct disk, making us help from the indications present in the MODEL and CAPACITY fields. Once the disk is located, click on Continue and confirm where necessary, so as to start the low-level formatting process. This operation (very long, it can take even more than 4 hours) will replace each sector of the disk with 0s (zeros), so as to make the data contained inside completely unrecoverable.
At the end the disk will appear as unpartitioned and uninitialized, ready to be sold or sold to users we don't know.
This program is available for free, but has an automatic speed limiter (180 GB per hour at 50 MB / s), which prevents its massive use; to unlock the maximum speed it can be useful to buy a user license, but if we are not in a hurry we can let the program act all night and wait for the end of the process without problems.
A free program that formats the main disk of the P C by erasing everything completely and definitively is Darik's Boot And Nuke or DBAN, which works on every computer with Intel or AMD processor and on Apple Mac machines.
The program to be downloaded is an ISO image to be burned onto a CD. Once the DBAN cd has been inserted into the computer, restart it and start it from the cd disk using the boot option from the bios (generally with the F12 key when the white writing appears on a black background at the beginning).
In the screen that appears, press Enter and wait for the program to load. In the next screen you can choose which disk you want to erase and format, selecting it with the space bar. To start the deletion process, press F10.
With the M key you can choose a cancellation mode based on the passes to be made. For any expert in the sector, DBan is the best program to delete files from a hard disk without the possibility of recovering them, even better than paid programs.
As easy as it is to use, the complete elimination procedure can be very long.
READ ALSO: Initialize and format new or unrecognized disk (Windows)
3) Format Hard Disk or SSD with a Linux system on a USB stick
The second method that we can use to achieve true low-level formatting involves the use of Linux and can also be used without removing the disk from the PC or notebook that we intend to sell (which is instead necessary to use the program shown above).First we install any GNU / Linux distribution on a USB stick, so that we can operate outside the operating system on the disk to be formatted; to do we download a GNU / Linux distribution in ISO format (like Ubuntu for example) and see how to proceed by reading our guide -> Install an ISO Linux on USB .
After preparing the stick with Linux, place it on a free USB port on the PC and restart the PC by setting the boot mode on the stick; if we don't know how to do it, we can read an easy guide that we made on the subject -> How to change the boot order of the computer .
Once we arrive in the main screen of the Linux operating system (which will start from the stick), we open the menu in the upper right or the menu in the lower left (based on the downloaded Linux system) and look for the Terminal or Terminal program.
A kind of prompt will open (even if it is not a correct term, it remembers it very closely) in which to type the commands to format the disk present on the PC at a low level.
Let's start typing the command to see the connected disk in detail, so as to recover a fundamental code for formatting:
sudo fdisk -l
After launching this command, the terminal will textually show us the information on the disk and any partitions present.
For formatting, we recover the code in the " Disk / dev / sda " string where the path of the hard disk associated with the computer we are using is present.
After obtaining this information, we run the following command based on the information obtained from the previous command:
dd if = / dev / zero of = / dev / sda bs = 512
Instead of of = / dev / sda we will have to use the exact path of the disk as recognized by Linux.
After running this command, the disk in question will be formatted and each sector of the disk will be filled with 0's (zeros), so as to make the disk completely unrecoverable.
Also in this case the process is very long (even over 5 hours), therefore better to leave it to act at night; at the end we will have a disc as new and ready to be sold or sold to third parties.
4) Full format on SSD
The programs and steps shown so far are fine for mechanical disks, but are superfluous for SSDs, since the latter are extremely sensitive to very intense writing processes (and previous programs write continuously for several hours, effectively shortening the life of the SSD).To completely format an SSD, simply delete it with quick formatting as seen in the first point of the guide and delete any traces using the TRIM command, used by default to remove the residual data present in the cells.
To start this command, connect the SSD to be formatted as a secondary disk via USB or internal drive (with SATA), open the Windows Start menu and search for Defragment and optimize drives .
The disk management system will open: we identify the SSD among the disks present, select it and finally click on Optimize at the bottom.
Now the SSD is fully formatted and any traces deleted from the cells, making file recovery difficult.
Alternatively, we can erase the SSDs using the tools made available by the various solid state drive manufacturers, who also offer a drive management and erase tool.
For example SanDisk offers the free SanDisk SSD Dashboard tool for its SSDs.
Once installed on the system (where we previously connected the SanDisk SSD to format), let's go to the Tools menu and then to Erase drive .
If the SSD is secondary on the system in use, we can use the Sanitize entry to delete all sectors and carry out the TRIM command. If the SSD is instead the one that houses the system, we can format it completely by creating a USB formatting stick directly from the Delete drive screen seen previously, we will just have to connect an empty USB stick and click Create USB drive .
Once this key is created, we restart the PC with it inserted and format the SSD to prevent data recovery.
If we use other types of solid state drives, we can download the related SSD tools we have already talked about, including:
- Samsung Magician SSD
- Toshiba SSD Utility
- Intel SSD Toolbox
5) Conclusions
If you intend to permanently delete only some files, without completely formatting them, you can use programs to delete files in a safe and definitive way ; alternatively we can delete the free space of the disk without touching the other files and without formatting.Still talking about hard drives, in other articles we have reported the best programs to check the health of the disk and those for error checking with scandisk or checkdisk on Windows.
