What Is the Purpose of Formatting a Hard Drive?

By Ashley Poland

You can format either external or internal hard drives.
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Formatting a drive isn't just for fixing a broken computer; you can use it to handle any number of routine computer maintenance tasks. While formatting your hard drive is a bit more permanent than sending a file off to the trash can in terms of erasing data, it doesn't really remove your data in a serious way – a well-trained professional could still coax your data off a formatted drive. As such, formatting a drive is appropriate for some situations while not being right for others.

Removing Your Data

The most common reason for formatting a hard drive is to remove the data. If you're just erasing the data for your own use, such as switching the hard drive to a different computer or setting it as a secondary drive, formatting is fine even though it's not totally secure. If you're removing data to donate or sell a hard drive, you should consider more permanent methods for erasing data from your hard drive.

Changing Your Operating System

Just because your computer came with Windows doesn't mean you're stuck with it; you might want to change to a competing operating system. You also might need to upgrade an old computer to a newer operating system. Whatever the case, if you want to get a fresh start with a new OS, formatting is the way to go. It removes previous system files and settings and ensures that you're not bringing any old bloatware or malware over from your old OS.

Changing Your File System

There's more than one system available for your hard drive. For instance, Windows systems use the NTFS system for hard drives, while OS X hard drives are formatted into the HFS+ system and Ubuntu drives use Ext4. The only file system that every OS can read is FAT, which is the default for USB thumb drives. If you're planning to change the file system of a hard drive, whether its in your computer or an external hard drive, formatting is the way to go.

Erasing Partitions

Most new computers come with a rescue partition instead of a boot disc – which you'll need when you must revert to an earlier version or manage your system. If you previously partitioned your system to separate partitions, such as when dual-booting two different operating systems, your computer treats each partition as its own drive. When formatting a hard drive, you can create a single partition in place of several partitions, giving you better use of all your hard drive space.