How to Reformat an External Hard Disk

by Kevin Krause

Overview

An external hard disk drive can come in handy in a variety of cases. Whether you simply need extra storage space for your pictures and music, would like to create a bootable disk drive containing an alternate operating system, or would like the security of backing up your computers files, an external hard disk is often the answer. Before you can use a new hard disk or if you wish to reclaim a drive you already own for a new use, it must be formatted. Reformatting your disk to work with your computer and operating system is a simple process.
Reformatting in Windows

Step 1

Connect your external drive to your PC using the proper connecting cables. Most modern external hard disks will use either USB or FireWire connections. If needed, connect your hard disk to its power supply.
Step 2

Double-click the "My Computer" icon. The external drive should be show in the list of available drives. If the drive does not appear, reboot the computer and it should now show in the drive list.
Step 3

Right-click on the external hard disk in the list of drives and select "Format" from the drop-down menu.
Step 4

Label the volume in the dialog box that pops up. Select the file system you wish to format the drive to work with. A drive being formatted to work with Windows XP and later Windows operating systems should be formatted to "NTFS." Windows 98 and earlier operating systems use the "Fat 32" file structure.
Step 5

Click "OK" in the "Format" dialog box.
Step 6

A warning will appear making sure you wish to format the drive. Click "OK" and your drive will begin formatting. The format time will vary depending on the size and speed of the hard disk.

Reformatting in Mac OS X

Step 1

Connect your external drive to your Mac using the proper connecting cables. Most modern external hard disks will use either USB or FireWire connections. If needed, connect your hard disk to its power supply.
Step 2

Launch "Disk Utility" located in the "Applications" folder under "Utilities." Select the external hard disk from the list of drives on the left.
Step 3

Click the "Erase" tab. Under "Volume Format" select the file structure you would like to use. "Mac OS Extended (Journaled)" is the default Mac OS X file system. Enter a title for the external drive in the "Name" field.
Step 4

Click "Security Options..." and choose the method of reformatting for the drive. Click "OK."
Step 5

Click the "Erase..." button in the main "Erase" pane. A pop-up will appear asking you to confirm that you want to erase and format the drive. Click "Erase." A progress bar will appear and your drive will now begin formatting.

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Computer External hard disk drive Connecting cables
Computer
External hard disk drive
Connecting cables
An external disk drive will only be compatible with the file system it is formatted for. Refer to the resources for tips on how to create a disk that is compatible with both the Windows and Mac operating systems.
An external disk drive will only be compatible with the file system it is formatted for. Refer to the resources for tips on how to create a disk that is compatible with both the Windows and Mac operating systems.
Once a drive is formatted, any data stored on it will be permanently lost. If you wish to save any files from your external hard disk, back them up onto another drive before formatting.
Once a drive is formatted, any data stored on it will be permanently lost. If you wish to save any files from your external hard disk, back them up onto another drive before formatting.