How to Format a Hard Drive

Once formatted, the hard drive will allow you to store files and install programs on your computer to it. The format type you choose determines the compatibility of the drive. After formatting, all data on the drive will be completely erased, so don’t forget to back up everything before proceeding. Let’s learn how to format the second (or third, fourth…) drive on Windows and OS X, as well as how to format the boot drive on both operating systems. You will also be able to securely erase all data on the hard drive.

Table of Contents

Format the secondary hard drive (Windows)

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Back up any data you want on the drive. Formatting the drive will erase all data on it, so make sure you back up everything you need in a safe place. We can then restore this data to the new drive.

You cannot back up installed programs. These programs need to be reinstalled on the new drive. However, you can still back up settings and preference files.
See also this guide for how to back up data.

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Install the hard drive. If this is a new drive, you need to install it on the system. See also this guide for how to install the built-in hard drive. With an external hard drive, you can plug it into your computer via a USB port.

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Open the Computer/My Computer/This PC window. You can do this by accessing the Start menu or pressing ⊞ Win + E . This window will show all the drives connected to the computer.

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Right-click the drive that you want to format. Select Format… to open the Windows disk format tool.

You need to make sure you select the correct drive. All data will be erased when the drive is formatted.

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Select the file system. The file system is how the hard drive stores and categorizes files. The file system determines which devices the drive is compatible with. If this is a built-in drive and you only use it on a Windows computer, choose NTFS. For external hard drives, FAT32 or exFAT is the appropriate choice.

FAT32 and exFAT can be overwritten and read by all operating systems today. FAT32 is an outdated file system and does not support files larger than 4 GB, but can be read by almost any operating system. exFAT is very flexible, but this file system does not work with old operating systems like Windows 95.
In general, exFAT is the most suitable option for external drives. This system is compatible with most operating systems and can store the largest files.

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Name the drive. If you mainly use this drive once, the naming will help us know what’s inside. For example, if this secondary drive is used to store music, movies, and photos, the name “Media” will help you quickly figure out what’s in it.

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Select Quick Format or not. The Quick Format process is suitable for most users and will be much faster than standard formatting. Only proceed with regular formatting when you suspect a problem with the drive. The standard formatting process can fix some errors.

The Quick Format option does not guarantee that the data will be securely deleted. If you need to erase the entire drive, see the end of this article.

Format the secondary drive (OS X)

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Back up any data you want on the drive. Formatting the drive will erase all data on it, so make sure you back up everything you need in a safe place. We can then restore this data to the new drive.

On OS X, programs are safely backed up when you use the Time Machine (TM) integration feature. This saves a lot of time because then you won’t need to reinstall all the programs manually. With a simple copy, in many cases, the software will work properly because the Mac program is in one large file, not many small files scattered on the system.
Settings and preference files can still be backed up and in place thanks to TM, we won’t need to do it manually.
See also this guide for how to back up data with TM

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Install the hard drive. If you format a new hard drive, you need to install it on your system. See also this article for how to install the built-in hard drive. For external hard drives, you can plug them into your computer via a USB cable, FireWire, or Thunderbpt.

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Open Disk Utility. Click Go and select Utilities . If there is no Utilities option, you can select Applications and double-click the “Utilities” folder. Then, open the Disk Utility program.

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Select the drive from the list on the left. All connected drives will appear in the left pane of the Disk Utility window. You need to be sure to select the correct drive.

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Click the “Erase” tab to open the drive formatting tools.

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Select the file system. The file system is how the hard drive stores and categorizes files. The file system determines which devices the drive is compatible with. Use the Vpume Format drop-down menu to select the file system. If this is a built-in drive and you only use it on OS X, select “Mac OS Extended (Journaled)”. For external hard drive and simultaneous use on PC, you need to select “exFAT”.

FAT32 and exFAT can be overwritten and read by all operating systems today. FAT32 is an outdated file system and does not support files larger than 4 GB, but can be read by almost any operating system. exFAT is very flexible, but this file system does not work with old operating systems like Windows 95.
In general, exFAT is the most suitable option for external drives. This system is compatible with most operating systems and can store the largest files.

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Name the drive. If you mainly use this drive once, the naming will help us know what’s inside. For example, if this secondary drive is used to store music, movies, and photos, the name “Media” will help you quickly figure out what’s in it.

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Start the formatting process. Click Erase to begin formatting the drive. This process will only take a few seconds.

Formatting the drive in this process does not safely erase the data completely. If you want to make sure that the data has indeed been deleted, see the end of the article.

Format the boot drive (Windows)

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Back up the data you need on the drive. Formatting the boot drive will erase the operating system and all files stored on it, so you need to be prepared to reinstall the operating system onto the drive. Having a backup of your important files will make the conversion process much easier.

See also this guide for how to back up data.

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Insert the Windows installation disc. You can also use a bootable disc or a LiveCD. So we will proceed to boot this disk instead of the hard drive, so you can format the hard drive.

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Set up the computer to boot from disk. You need to reset the boot order in the BIOS in order for the computer to boot from the disk. See also this article for how to set the boot order.

To open the BIOS, restart the computer and press the setup key. This key is usually F2 , F10 or Del .

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Navigate through the settings screens. You’ll need to start the installer and navigate through the first few pages to get to the screen that lists the drives to be installed. We will begin the custom installation of Windows.

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Select the drive you want to format. A list of all drives and partitions on them will appear. Select the drive you want to format, then click the “Format” button at the bottom of the list. The drive will be formatted to NTFS.

We can just format the boot drive as NTFS.

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Reinstall Windows. Now that the drive is formatted, you can reinstall Windows or Linux into it. We need an operating system to use on the computer, so let’s find out:

How to reinstall Windows 7
How to reinstall Windows 8
How to install Linux

Format the boot drive (OS X)

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Back up the data you need on the drive. Formatting the boot drive will erase the operating system, so you need to be prepared to reinstall the operating system. Having a backup of your important files will make the conversion process much easier.

On OS X, programs are safely backed up when you use the Time Machine (TM) integration feature. This saves a lot of time because then you won’t need to reinstall all the programs manually. With a simple copy, in many cases, the software will work properly because the Mac program is in one large file, not many small files scattered on the system.
Settings and preference files can still be backed up and in place thanks to TM, we won’t need to do it manually.
See also this guide for how to back up data.

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You need to make sure that your computer is connected to the Internet. We need an Internet connection to reinstall the operating system at the end of the process. See also this article for how to connect your Mac to the Internet.

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Reinstall the computer. Click the Apple menu and select Restart . Hold down ⌘ Command + R while the computer restarts. This will open the boot menu.

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Select “Disk Utility” from the boot menu. The startup version of the Disk Utility program will open.

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Select the hard drive from the list on the left. All drives will be listed in the left pane of Disk Utility. You need to make sure you select the correct drive because after formatting, any data on it will be erased.

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Select the file system. The file system is how the hard drive stores and categorizes files. The file system determines which devices the drive is compatible with. Use the Vpume Format drop-down menu to select the file system. If this is a built-in drive and you only use it on OS X, select “Mac OS Extended (Journaled)”.

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Name the drive. For example, if you are reinstalling the operating system to the disc, name it “OS X” or similar.

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Format the drive. Click Erase to format the drive. This process only takes a few seconds.

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Close Disk Utility. You will return to the boot menu.

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Reinstall OS X. Select “Reinstall OS X” to start reinstalling the operating system.

Safely erase hard drive

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Back up the data on the hard drive that you want to save. After the hard drive is securely erased, there is definitely no way to recover. A properly wiped hard drive can take a whole day for a government supercomputer to hope to recover a fraction of the files. Because of this, make sure that all the data you need is saved.

See also this guide for how to back up data.

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Download DBAN. DBAN is a hard drive format program designed to securely wipe data from a drive by overwriting it multiple times. This process will prevent information from being restored using a data recovery program.

DBAN does not work with solid state drives (SSDs). You will need to use another program, such as Blancco.

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Burn DBAN to disk. DBAN is downloaded as an ISO file which is a disk image. When you burn the ISO file to the disc, the computer will be able to boot directly into the DBAN interface.

See also this article for how to burn ISO file to DVD.

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Boot from DBAN disk. Insert the DBAN disk into the computer and reboot. Select this drive as the primary boot device.

Windows – You need to set up the optical drive as the boot drive from through the BIOS menu. See also this guide for how to set up the boot order.
OS X – Hold down C as the computer restarts. In a few moments, DBAN will start up.

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Select the hard drive. Press ↵ Enter on the main DBAN screen and select the drive using the arrow keys. You need to be sure to select the correct drive if there are multiple options available.

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Select the delete method. “DoD” is a secure method of deleting data that is just enough for most users. If you have extremely important information, you can choose “8-Pass PRNG Stream”. The hard drive will be wiped 8 times with random numbers and this process will completely erase the data on it.

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Start formatting. After selecting the erase method, the formatting process will begin. If you choose DBAN, the process may take several hours to several days, depending on the deletion method and the size of the hard drive.

Warning

It is not recommended to try to connect an external hard drive to multiple computers at the same time as this may damage the partition and corrupt the data.
Make sure you back up all your files before you format the drive.

Steps