Before you hand over your laptop or an old hard drive to a friend or a stranger, you have to be very careful and beware. When you delete a file or data from your drive, it’s not really gone. Your system marks that occupied space as free space now and you can recover those deleted files on your Mac. Generally new data overwrite that space making the deleted data harder to find. So you have to make sure that all personal and important are cleaned off. Formatting won’t help you in this case. Instead you have to securely wipe the hard drive.This guide will tell you how to securely wipe a hard drive on your Mac.

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Why you need to wipe a hard drive?

Wiping your hard drive data is necessary as it may be recovered by it’s new user and that person can use that data to harm you. Some things such as identity theft, credit-card fraud, bank fraud, hacking, your auto save passwords, emails, browsing history and personal content can be used to blackmail you or commit crime in your name. So it is advisable to erase your hard drive to reduce the risks.

How to Securely Erase Data from Your Mac and External Drives?

You can use Disk Utility to securely erase hard drive in mac or an external hard drive. All you have to do is follow the steps given below:

1.Wiping your hard drive will erase everything. So it’s better to back-up your data in an external source before wiping your drive.

2.Open the apple menu and restart your computer. Then wait for your mac to restart.

3.After the system restarts press and hold the Command+R keys.

4.Hold the Command+R keys until you see the Apple logo.

5.After that a window named “OS X Utilities” pops up.

6.Click on the Disc Utility option as shown in the image below and click on continue.

7.Select the hard drive you want to erase from the available drives list in the left column.

8.You have to be very careful at this moment. Make sure you select only hard drives and not partition.

9.Once you have selected your drive, click on ‘Erase’ button.

10.After doing so the system will ask you to name the hard drive after erasing it and how you want to format the drive. The default settings are preferable.

11.Then select the ‘Security Option’ button.

12.A window will pop up asking you how you want to erase your drive. Fastest way is the default. Adjust the slider and select the option which you want. You can choose from the following options.

(a)Fastest (Least preferred): This option doesn’t erase your drive securely and a disc recovery application may be able to recover the files.

(b)Option 2:  It erases the information used to use your files and writes over the data two times.

(c)Option 3: It erases the information used to use your files and writes over the data 3 times.

(d)Most secure: It erases the information used to get access to your files and writes over the data 7 times.

As the option 1(fastest) is least secure it is foolish to choose it. Option 4 is most secure but it will take a lot of time. So I suggest you to choose from Option 2 or Option 3 depending how securely you want to wipe it out.

This method works for all hard drive (internal or external). But if you want to erase your startup drive you have to boot your computer from an external source. You can use Diskmaker X to create a bootable external source.

How to Securely Erase a Mac SSD or a flash drive?

Solid state drives or flash drive stores data differently. So using Disc Utility is a bad choice. It may affect your drive memory cells or affect it’s performance. There is a simple way to erase your SSD by using FileVault 2 . In FileVault 2 the full-disk encryption (FDE) option keeps your startup drive encrypted all times. When you boots your system with a FileVault encrypted account, OS X encrypts everything written to disk.

You can erase the File Vault encrypted drive using Disc Utility. But before erasing the system will ask you to unlock the drive. To unlock the drive you need to enter the password for the FileVault enabled account. If successful, disc will be unlocked and erased.

Erasing a File Vault encrypted drive will make the drive data irrecoverable.

What if you can’t access the hard drive?

If you cannot access the drive then Disc Utility won’t help you in this case. Professional data recovery companies may help you in this case. Hard drive platters can be extracted from the drive enclosure and read out using specialized equipment. So smashing or breaking your hard drive is your best option.

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You can use FileVault,Disk Utility and Mac Washing Machine to encrypt and erase your startup or external hard drive.You can always hire a professional service.After wiping your mac hard drive you can wave it goodbye.