How to make sure your personal data is deleted before selling the device

make sure that your personal data is deleted

How to make sure that your personal data is deleted

Personal devices such as desktop computer tablet or mobile phones contain a lot of your personal information. If you are considering selling, recycling, or donating it to someone, you must ensure that all information on it is deleted correctly. So that no one can take it back.

There are simple ways to make sure you delete your personal data that you can do yourself, and the method that you follow in securing your private information depends on the operating system and the type of storage on your device.

Let us explain to you in detail the steps and foolproof methods:

1. Keep a copy of your data before deleting

Before cleaning your computer and deleting data stored on it, make sure you have a backup copy of any files you need, and disable any programs that require doing so. For MacBooks, Apple recommends that you sign out of all iCloud services, including iTunes and iMessage.

Then you need to know the storage type on your computer. On Windows computers, finding this information is a little more difficult, but the easiest way is to open the Defragment and Optimize Drives tool, then type "defragment" in the search menu on the taskbar.

On a MacBook, click the Apple logo, then About This Mac, then select the Storage tab. Typically, this page indicates whether it is "solid-state" or "flash storage" for SSD, or "hard disk drive" for mechanical hard drives.

The following directions will guide you to clean your computer with any device running Windows 10, as well as most Mac computers. If you have an older version of Windows, or if you wish to perform the operation using various means to delete files, your best option is the standalone tool called Dban.

2. If you have a steady-state storage medium, start with encryption

If you purchased your computer in the last few years, it most likely has a steady-state storage medium. SSD media is faster than older mechanical hard disks and uses flash memory instead of magnetic disks. The downside of this technology, however, is that securely deleting files on an SSD is extremely difficult. The SSD uses a technique called wear leveling to extend its life, but one of the side effects of this process is the possibility of data remaining on a storage medium even after it is erased.

So, instead of using special software to erase the contents of the SSD, you'd better encrypt the storage medium, using a mathematical process to confuse the data with a passkey that no one else has. Without the key, files on the storage medium look like talismans, and even if someone were to recover the files, they would not be able to open them.

3. Encryption methods for Windows and Mac

The good news is that encrypting a storage medium is simple. This is something we recommend doing for every SSD computer, even if you aren't going to sell it. You can also encrypt mechanical hard drives for the same purpose, but the process takes a very long time, and it is easier to just delete the data from them.

Windows encryption method:

If your computer is running Windows, encrypting your storage media might be a bit complicated, depending on the version of Windows on your computer and the components that you installed.

Some Windows laptops have encryption by default. To be sure:

  • Click the Start menu, then choose Windows Administrative Tools, then System Information (or type "system information" in the search menu on the taskbar).

  • Look for Device Encryption Support, and if you find it and it says "Meets prerequisites," it is already available on your device.

If this option is not available, look for the self-encrypting tool, BitLocker, which is available in the Pro, Education, and Enterprise editions of Windows 10, then follow these steps:

  • Open Control Panel.
  • Click on System and Security.
  • Click on Manage BitLocker.
  • Click on Turn on BitLocker.

BitLocker is also able to encrypt external storage media, including SD cards and flash drives, and is the safest way to delete files on those media before formatting them.

If you do not have BitLocker, you should resort to separate software. We recommend VeraCrypt, but you should know that the encryption process is more complex than BitLocker. Some SSD manufacturers may also provide software to safely erase SSD media.

Data encryption method for Mac:

Macs have had the free encryption tool called FileVault 2, since 2011, and the steps are the same in all versions of macOS:

  • Open System Preferences.
  • Click on Security & Privacy.
  • Choose the FileVault tab.
  • Click on Turn on FileVault.
  • In OS X Yosemite and later, you are required to either use your iCloud password or use a recovery key. Since you are cleaning the device, both options are acceptable.

4. Clean and reset your computer

This is your last chance to recover any files, so double-check before continuing.

Once you activate SSD encryption, or if your device has a mechanical hard disk, all that remains is to configure the storage medium and reset the operating system. When you do this, you have two options: 

keep your files (which is useful if your computer is running slow or has other problems) or delete everything, which will delete all your files stored on the device and reinstall the operating system. If your computer has an SSD encrypted, this step is not necessary if you are going to recycle your computer, but it is a useful step.

Reset Windows:

  • Open Settings and choose Update & Security.
  • Click the Recovery tab, then Get Started.
  • Choose to Remove everything.

Follow the required on-screen commands, and your device will restart... Depending on the size of your storage media, this may take a few hours. Finally, it will open the Install screen, and you can turn it off.

Reset method for Mac:

For Mac, you have to start your device and instruct it to enter a special menu before opening the operating system:

  • Open your computer (or restart it).

  • Immediately press and hold the Command and R keys on the keyboard until the Apple logo appears. Once this happens, release both keys.

  • Your device will enter a special restore menu. Choose Disk Utility from the menu.

  • Choose your storage media and click the Erase button. It's okay to keep the basic configuration and layout settings.

  • Choose Security Options. If you have encrypted the storage media, you can leave it on the default option, but if you are preparing a mechanical hard drive, you should move it at least to the second layer of security, "3-pass secure erase".

If Disk Utility finishes wiping everything out, you can shut down your computer. Or you can return to the utility menu and choose Install macOS if you want to configure the device for the buyer, but this is not necessary.

How to reset Chrome OS:

Google offers encryption by default in ChromeOS, and the reset process is simple:

  • Open Settings.
  • Type "Powerwash" in the search bar.
  • Click on Reset.
  • Click on Restart.
  • Click on Powerwash and then Continue.

Note that Chromebooks connect to your Google account, which still stores most, if not all, of your data. When you use Powerwash, it automatically logs you out of your Google account.

5. Clean and reset smartphones and tablets

Just like with a computer, you need to take steps to clean and reset your phone or tablet before selling it. The process is much easier on portable devices than on computers.

Encryption for iOS:

Encryption is available by default on iPhones and iPad, so you just have to reset your device. First, make sure you have a recent backup of your data, then disable Find My. Once done, you can reset your phone or tablet, follow these steps:

  • Open Settings.
  • Click on General.
  • Click on Reset.
  • Click on Erase All Content and Settings. Enter your passcode when prompted, then tap Erase.

When the process is finished, your iPhone or iPad will restart, after which you can turn it off.

Encryption for Android:

Encryption is available by default on modern Android devices, but make sure to enable it by opening Settings, then Personal, then Security (it may be found in different places on some Android phones). Also, make sure to have a backup copy of your phone data. Then, you can reset the device. The process varies depending on the phone, but here's how to do it on an Android phone:

  • Open Settings.
  • Click on the System and open the Advanced drop-down menu.
  • Click on the Reset options.
  • Click on Erase all data.
  • Click on Reset Phone, enter your PIN, and choose Erase Everything.


For most people, coding and cleaning your hardware is enough, although you can destroy it if you don't intend to give it to someone else. But if you own a laptop that is still working, consider recycling or donating it.

Whether you are giving someone else's computer or sending it to a recycling center, cleaning your personal data is an essential first step, so take the time to get it right.

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