The spring cleaning period is nearly over, and it’s time to finally dispose of that outdated computer. However, exercise caution before selling, donating, or recycling it.
You might be transferring confidential details.
Even if you believe you have removed all data from it, your previous computer might still contain numerous private details that you wouldn’t want others to see.
In a 2019 study
A study conducted by the University of Hertfordshire, supported by the cybersecurity reviews platform Comparitech, involved buying 200 second-hand hard drives from the U.S. and the UK. Upon examination, it was discovered that information persisted on 59% of these devices, such as scanned passports and driver’s licenses, banking records, electricity invoices, and “private images.”
Simply clicking “Delete” and clearing the Trash in macOS or the Recycle Bin in Windows isn’t enough. This is because your computer keeps track of all file locations through an index. When you delete a file, it only removes its reference from this index, indicating that the storage area is available for new data. However, as long as the system hasn’t overwritten that space with new information, the deleted files can still be accessed. Even basic file recovery programs can retrieve them—let alone advanced forensic tools used by professionals.
Follow this method to ensure your information is completely erased—even from a device that fails to power on.
Exit and save data
Sign off and return
End session and disconnect
Log out and revert
Terminate connection and exit
Close account and step away
Shut down and sign out
Pause and leave system
Cancel access and logout
Disconnect and back up
Begin by securing all items you wish to retain. You might transfer files to an external hard drive by dragging them over, or utilize backup programs like the Time Machine application found on macOS. Additionally, you have the option to store data online through platforms such as Microsoft OneDrive, Apple iCloud, Google Drive, Dropbox, or similar services. (Avoid clearing the Trash or Recycle Bin; the formatting procedure will handle this.)
Afterward, sign out of apps or games that require an internet connection, ensuring the license is no longer linked to your previous device. Do the same for services such as Gmail or Facebook, along with web browsers like Chrome that synchronize your information online—in case an improper erasure enables the new user to gain entry to these accounts.
An additional measure for all types of computers involves ensuring your data is encrypted—transformed through complex mathematical processes using lengthy sequences of random numbers and characters known as encryption keys. During the erasure procedure, these keys are removed to guarantee that any remaining files on the device cannot be accessed.
Your subsequent actions will vary depending on your operating system.
Clearing out a PC
Windows 10 and the latest version of Windows 11 include a feature known as ”
Reset this PC
which, when configured properly, completely removes your data. Firstly, ensure your operating system is current, since Microsoft has recently resolved an issue that occasionally led to the reset failing. Press the Windows key, type ‘updates,’ and choose ‘Check for updates.’ Install all applicable ones.
Check the encryption features now. On Windows 10 or 11 Home edition, press the Windows key and search for “device encryption settings.” Select “Device encryption settings” on the following page, and ensure the toggle beside “Device encryption” is turned on. For Windows Pro, Enterprise, and Education editions, there’s an encryption tool known as BitLocker. To activate it, click the Start menu, enter “bitlocker,” and choose “Manage BitLocker” from the options displayed. (All versions of Windows 10 and 11 automatically encrypt removed files.)
You’re now prepared to reset your device. Press the Windows key once more, type “Reset this PC” into the search bar, and select the result. On the subsequent page, choose “Reset PC” (for Windows 11) or “Get started” (for Windows 10), followed by clicking “Remove everything” on the next interface. Next, pick “Local reinstall.” (Should this not function properly, attempt using the “Cloud download” choice instead.) Afterward, hit “Change settings,” and on the ensuing screen (within the “Clean data?” section), set the slider to “Yes” and confirm with “Confirm.” Proceed by tapping “Next” (on Windows 11) or “Reset” (on Windows 10). For Windows 11, you’ll have to click “Reset” one additional time. Allow the procedure to complete over several hours.
“Reset this PC” removes your personal files, applications, and preferences, signs you out from your Microsoft account, and turns off the “Find My Device” function, thereby disconnecting the device from your profile. Following this, an intensive erasure process begins. Encryption keys are removed, rendering all encrypted information permanently unreadable, and the ‘Clean data’ setting replaces the binary code that previously stored your data on the hard drive. Additionally, a fresh installation of Windows is performed.
The MacOS method
Apple’s “
Erase Assistant
“feature was introduced in macOS 12 Monterey released in 2021. If your operating system is outdated, you might have the ability to upgrade it. To move from an earlier version of the OS to Monterey or a newer release, select the Apple menu, followed by “System Preferences” and “Software Update.” Should the update procedure not function properly, refer to “If all else fails” further down for an alternative solution.
Similar to Windows, the “Erase All Content & Settings” procedure should begin with encryption. On more recent Mac models (introduced sometime between 2018 and 2020, based on the specific device), data is encrypted by default. Still, for added security, enable a setting known as FileVault, which provides encryption for older devices and offers additional protection for newer ones. Select the Apple logo, followed by “System Settings” (or “System Preferences” if using Monterey). From the following screen, choose “Privacy & Security” (or “Security & Privacy”), then select FileVault.
It’s now time to reset your device. Tap once more on the Apple logo and select “System Settings” (or “System Preferences”), choose “General” from the left menu, and then tap “Transfer or Reset” located at the lower right corner. On the following page, select “Erase All Content & Settings.” (On Monterey, this option can be accessed directly from “System Preferences.”)
This procedure logs you out of Apple services, disables “Find My” and “Activation Lock” security features, ensuring the device is no longer linked to your account, and removes all your personal information, configurations, applications, and additional content. It also eliminates the encryption keys, irreversibly mixing up any remaining data.
If all else fails
If your personal computer or MacBook is too outdated to support a current wiping procedure, you still have another choice before consulting a professional. For Windows systems, various specialists suggest using the KillDisk application. The $49.95 Pro edition operates via a USB stick and replaces the binary information stored on your hard disk with only zeros. Once completed, your machine won’t be able to start up Windows again without re-installing the operating system.
For a MacBook, your most effective choice involves a detailed procedure that
Apple describes online
.
If these steps seem overly complex, or if your device fails to power on at all, try using Apple’s
recycling program
For Apple computers or a waste management service that provides hard drive destruction (or shredding) along with recycling options for both types of systems. Choose those that provide a certification of destruction to confirm the procedure was completed. For example, Ship ‘N’ Shred takes in drives or entire units, with costs covering postage starting between approximately $30 and $200.
Today’s technology creates numerous digital traces, yet you can still remove them from your outdated computer.
Sean Captain
is an author based in New York. You may contact him via
[email protected]
.
