What you have to do, and that everyone forgets, before selling your laptop or mobile phone on Wallapop

Getting rid of a computer, whether to sell it on a ‘marketplace’ like Wallapop or to give it to a friend or family member, is a more complex issue than it might seem at first, especially in Windows, in which a standard format does not eliminate the real data and leaves the recorded files exposed to anyone who can recover them with a program free.

We must take into account that not all operating systems work the same and the deletion processes change from Windows to Mac, just as they do from Android to iOS. In Windows, when a disk is reinstalled or erased using the default option (the well-known ‘Quick Format’), what happens is that the index (the file allocation table) is deleted, but the files actually remain on the disk, even though it appears empty and available to be written on.

In fact, Microsoft has a section on its website where it clarifies that this step is crucial “if you plan to give away, recycle or sell the equipment”, and it explains it perfectly when giving all the details about ‘Wipe data’ in Windows 10 and Windows 11. It is the function designed specifically for when the user wants to get rid of a computer to remove personal files, applications and settings in its entirety. The only thing is that it may take a little longer to completely erase the information stored on the computer.

Another thing to keep in mind, when you are going to erase the computer, is to know the type of internal storage technology of the laptop or PC with Windows, since there is a big difference in how the Microsoft operating system behaves when it is an HDD hard drive (the traditional ones) or it is an SSD (the fast and modern ones), and follow some steps or others before putting it on. sale.

If it is an HDD hard drive, activating ‘Wipe data’ is mandatory, since if it is not done, the files are recorded invisibly and anyone could recover them with a free program available on the internet. To ensure that we can deliver the Windows laptop to a buyer or as a gift to a family member or friend, we must make sure to perform a deep wipe when factory resetting the computer.

The steps to follow are simple: first go to Start > Settings, then System > Recovery (or Update & Security > Recovery in Windows 10), and in the ‘Reset this computer’ option, click ‘Start’ or ‘Reset your computer’. Next, select ‘Remove all’ to erase personal files, applications and settings.

The key step comes when you display the ‘Additional settings’ screen, where you click ‘Change settings’, and then activate the ‘Wipe data’ option (which in some versions may appear as ‘Do you want to clean the drive?’). After confirming, the laptop will begin the drive formatting process for secure data erasure.

SSD drives work differently thanks to TRIM technology. When the operating system deletes a file or performs a format, the TRIM command sends the order to the SSD to physically clean those memory cells. In fact, recovering data on an SSD after formatting the drive is much more complicated, although it is always recommended to use Windows’ ‘Wipe Data’ option, which is still the safest way to ensure that your hard drives are completely erased.

The process on an SSD with TRIM works this way: as soon as you click format, the ‘brain’ of the SSD blocks access to the old files. If someone tries to use a recovery program a second later, the disk will lie to them and tell them that there are only zeros. For 99% of users, the data is no longer accessible.

The actual cleaning will occur physically as soon as the laptop is left on without using it, since TRIM left the files to be deleted in a to-do list and will physically clean them from the memory cells. Leaving the laptop on for half an hour after formatting is more than enough to give the SSD time to complete the complete erase.data in the background.

“Unlike traditional hard drives, SSDs do not immediately erase data when they are marked as deleted. Instead, the actual erasure is postponed until the SSD’s garbage collection process is executed,” explains memory manufacturer Seagate from its website.

On Macs, apart from erasing the content, you don’t need to do anything, since the most modern ones are designed with encrypted storage factory. The system instantly destroys the encryption key, rendering all user data completely unreadable and unrecoverable in seconds.

“Flash storage on Mac computers with an Apple chip, or Apple’s T2 security chip, is encrypted at the hardware level using Apple chip cryptographic technology. By using the ‘Wipe Contents and Settings’ feature, the system securely destroys the encryption keys, making the data becomes cryptographically inaccessible immediately“, as Apple cites it from its support website.

Android imitates the Mac experience. Unlike Windows, which has to deal with the problem of working on millions of computers of different brands where the vast majority do not have encryption activated by factory default, and forces it to force the writing of data to perform a complete deletion of data, Google’s mobile operating system does use the deletion technique cryptographicmentioned in the Apple case.

Still, on Android there is a crucial step before selling the device on Wallapop or giving it away. Google’s system uses an anti-theft security system called FRP (Factory Reset Protection). If you do not log out before erasing your phone, “a person who has your Google account or the screen lock will be able to use it,” as Google quotes on its Android support page. If the new owner does not enter it, the device will be unusable.

To delete the user’s personal account, go to Settings > Passwords and accounts, then select the Google account and click on ‘Remove account’. Once you are free of accounts, you can proceed to perform a factory reset to erase all your data.

On the iPhone with iOS the process is simply identical to the Mac and is done in a matter of seconds, so you don’t need to do anything. Apple was a pioneer in implementing this system and all iOS devices are mandatory hardware encrypted so that “the erasure process obliterates all keys in executable storage and renders all user data cryptographically inaccessible immediately.”