Formatting a disk drive with Disk Utility in OS X

At times, you may have the need to erase and re-use a hard drive, solid state drive, or even a USB flash drive so it can be used for alternative purposes. Fortunately, your Mac comes with all the tools you’ll need to do this, making it super simple for you to erase and format that drive for your needs.

In this tutorial, we’ll show you how you can format a USB flash drive using the Disk Utility built into your OS X operating system. This process also works with external hard drives, internal solid state drives, and any other drive that doesn’t contain your operating system on it.

Why format a drive

In some instances, before you can properly use a drive for the new purposes you plan to give it, you will need to format it using the proper file system. For a drive that you will use as a universal sharing drive, such as a USB flash drive that you intend to use on OS X, Windows, and/or Linux systems, you want to use a universal file system, such as ExFAT.

Other file systems are also available for drives, such as FAT32 and NTFS, but FAT32 has a strict limitation that says no single file can be larger than 4GB, and NTFS is intended for Windows machines only and is great for hand-me-down hard drives that you want to re-purpose for a Windows PC you’re building.

So with that in mind, we’ll be formatting our USB flash drive with the ExFAT file system today, because it’s a universal file system that is compatible with most modern operating systems, and moreover it doesn’t have the silly 4GB file size limit.

Just a word of warning: formatting a drive will erase all of the contents of the drive, whatever style it may be (USB, internal, external, etc.), and it will henceforth be treated like a completely new drive being set up for initial use. You should back up all important files before proceeding to the next part of this piece, where we will take you through how to format your drive.

How to format your drive

So now that you’ve decided to format your drive, you’ll need to know how. It’s a very easy process and we’ll take you through each of the steps below:

1) Launch the Disk Utility app on your Mac and select the drive you wish to erase and set up as a new drive from the sidebar. In our case, we’ll be formatting the PNY USB 3.0 drive we’ve plugged into our Mac.

Formatting a disk drive with Disk Utility in OS X

2) With the right disk selected (be careful not the choose the wrong one), click on the “Erase” button at the top center of the Disk Utility app.

disk utility erase button

3) A pop-up box appears; enter a name for the drive as you want it to be known as henceforth, and then click on the “Format” drop-down box to see a list of options.

disk utility format drop down menu

disk utility drop down menu options

4) Pick the format you would like to use; in our case, we’ll be choosing ExFAT because it’s a universal format and works great for USB flash drives.

5) With your options configured how you would like them (you don’t have to modify the Scheme), go ahead and click on the blue “Erase” button.

disk utility format erase button

6) Disk Utility will begin un-mounting your drive and formatting it to your desired settings.

disk utility unmounting drive

7) After you’re finished, you’ll receive a confirmation alert telling you the format is complete. Click on the blue “Done” button to finish.

disk utility format complete

Congratulations! Your drive is now fully erased and should be like new. You can now re-purpose it for anything you need, whether it’s more internal storage, a new USB drive, or something else.

Wrapping up

Formatting a drive is a great way to remove unwanted files from a drive and to get it working like new again. If you have no use for a Windows-formatted drive that you want to use your Mac, or a bootable drive you’d rather use as a USB flash drive instead, formatting is the answer because you can set up that drive tailored around your personal needs.


If you found this tutorial helpful, leave us a comment below!