How to format a hard drive
This article will show how to format a hard drive using Disk Utility, a helpful application that comes with every Mac.
By Roman Loyola | Network World US | Published: 10:10, 21 April 2011
When you format a hard drive, you’re setting up the drive so it can read and write data on your computer. It’s not a task you’d do on a frequent basis. When you buy a new hard drive, it’s usually pre-formatted, so all you have to do is connect it to your Mac.
But there may come a time when you need to format a hard drive. For example, if you bought a hard drive that wasn’t specifically geared towards Macs, it’s probably formatted for Windows. Re-formatting the drive can help improve performance and is required if you want to use the drive with Time Machine. Another example: You bought a new Mac, and you’re giving your old Mac away. Formatting the hard drive erases the data.
This article will show how to format a hard drive using Disk Utility, a helpful application that comes with every Mac. It’s easy, and takes a few minutes. The steps here are using Mac OS X 10.6.7 and should be similar for older OS versions.
Step 2: Select a format
In the left column, select the drive you want to format. (In this example, I will format the 1.04GB Generic Flash Disk.) If you have a partitioned drive and you want to format one of the partitions but not the whole drive, select a partition. Click on the Format pull-down menu. A list of six formats will appear. You need to select one - but which one? Mac OS Extended is the format specifically for the Mac, and it comes in two key variations, Mac OS Extended and Mac OS Extended (Journaled). Mac OS Extended (Journaled) maintains a journal of disk changes, which is helpful in case the drive suddenly loses power or is otherwise unexpectedly unavailable. If you are formatting a drive that will be dedicated to a Mac, we recommend using Mac OS Extended (Journaled). Time Machine requires a drive or partition on a drive formatted with Mac OS Extended (Journaled). There are two other Mac OS Extended formats available that offer case-sensitivity. With these two formats, files with the same names but different case treatments (e.g. diary.doc or Diary.doc) are considered two separate files and can both reside on your drive. If you are formatting a drive that you want to use on both a Mac and Windows (such as a portable hard drive or flash thumb drive), consider using MS-DOS (FAT) or ExFAT. MS-DOS (FAT) has some limitations (such as a 4GB file size limit), while ExFat requires that a Mac be running OS 10.6.5 or later. Select a format and give your drive a name.