How To Safely and Securely Erase Hard Drives, Laptops and Smartphones

In an experiment to test the security of obsolete electronic devices, “Which? Computing Magazine” purchased 8 used computers off of eBay to see what residual data they could find. Though the previous owners had attempted to delete the data on these devices, the magazine was able to recover 22,000 files in total, some containing sensitive information like:

• Saved passwords
• Data in the recycling folder
• Tax documents
• Personal identification files

Unfortunately, this same process is conducted by thousands of criminals every day who collect the stolen data and sell it on the black market. 

So the question is, how do you really wipe a pc, hard drive, smartphone, or laptop? While it's not as easy as dragging the files to the recycling bin, there are several simple steps you can follow to erase all data from any device. First, let’s look at how to clear your information from one of the more commonly owned devices, a personal computer. 

How to Completely Wipe a Personal Computer (PC)

Step #1: Copy or Backup All Useful Files

The first step before you erase all the data on your computer is to backup all the files you do not want to lose. This includes: 

Any documents or media you need to use or want to save have to be copied or backed up before you begin the wiping process. If you do not, there will be no way to recover them later. 

Step #2: Log Out of All Accounts and Determine OS

Though it may seem unnecessary, it's always best to log out of any accounts that could be automatically signed into by opening a web browser. If the wipe fails for any reason, criminals can use your auto sign-in settings to access these accounts with ease. You’ll also want to determine what OS, or operating system, your computer uses. This will help you determine which set of instructions to follow to complete the wipe.

Step #3: Erase All Data and Reset Your Computer

Once you’ve determined what OS you have, you’ll need to follow the instructions for that particular type of operating system. Here are the instructions for two of the most popular operating systems, Windows and Mac. 

How to Wipe a Windows Computer

If your computer is running Windows 10, follow these steps.

1. Select “Update & Security” from your computer’s settings.
   
2. Under the “Recovery” section, click the “Get Started” option.
   
3. Click “Remove Everything.”
   

If your computer is running Windows 11, follow these steps.

1. Select “Windows Update” from your computer’s settings.
2. Select “Advanced Options” and find the “Recovery” tab.
3. Click the “Reset PC” option, then select “Remove Everything.”

How to Wipe a Mac

1. If your computer is off, turn it on. As you turn it on, press and hold the “Command” and R keys until you see the Apple logo. Once you do, release the keys.
2. You should now see a special recovery menu. Click the “Disk Utility” option from this menu.
   
3. Choose the storage drive you wish to delete and click the “Erase” button. There is no need to change the format or scheme options.
   
4. From here, click the “Security Options” tab. If the drive you want to erase is encrypted, leave these options default. If it is mechanical, move the security settings up to “3-pass secure erase.” 

Computer Wipe Frequently Asked Questions (FAQs)

• How Do I Wipe a Hard Drive?

  The process to erase a hard drive installed on your computer is the same as it is for erasing the data of your entire PC. If you have an external drive, you can wipe it by writing the data over with a utility program. These programs are designed to automatically write over the data present on the drive so it can be sold or filled up with new data. Check to see what type of drive you have and what sort of programs would work best. 

• How Do I Wipe My Smartphone?

  To wipe a smartphone, first determine what OS your device is running. Two popular smartphone OS’s are Android and iOS.

How to Wipe an Android

1. Open Device Settings.
2. Select “System.” 
3. Open the “Reset” options. 
4. Select “Erase All Data” and follow the directions on-screen.
   

How to Wipe an iOS

1. Open Device Settings.
2. Click the “General” button.
3. Select “Transfer or Reset.”
4. Select “Erase All Content and Settings”. You’ll be prompted to enter your passcode.
5. Select “Erase.”
   

• How Do I Erase Everything on a Laptop?

  There is no difference between the procedure to erase a PC as there is a laptop. First, save all files you don’t wish to lose, then determine your operating system. Once you have, follow the instructions above to make sure your device is securely wiped of all data. 

• How Do I Clear Personal Information From My Computer to Sell It?

  First, follow these steps:

  1. Backup all useful data.
  2. Log out of accounts and determine OS.
  3. Navigate your computer’s settings to find the reset or remove options.
  4. Remove all data and shut down your device. 

  Once you’ve double checked all your data is removed, you are free to sell your device. You can do this through a second-hand store, pawnshop, online marketplace, or through a private sale. 

• Can I Wipe a Computer If I Don’t Have the Password?

  Depending on your operating system, yes, you can wipe the computer if you have forgotten or lost your password. For a computer running Windows, you need to put it into recovery mode by following these steps. 

  1. Turn off your computer and turn it back on.
  2. While your computer is booting up, turn the power off.
  3. Repeat this three times so the computer registers three failed reboot attempts.
  4. Your computer will now go into recovery mode. From this menu, select the reset option.