How to: Formatting External Drive for Mac


A brand new Disk Utility is accompanying the El Capitan release – in our books, it was about time. Yet, you can still use Disk Utility to format your startup drive. Basically, the steps are exactly the same.

We’ll go step by step on how formatting external drive for Mac should be done using the Disk Utility program for Apple’s new El Capitan. 

Remember to always back up your data, regardless of how safe you keep thinking you are. Also, before starting the format process, be sure that there is no crucial data on the drive. This should go without saying, but I’ve heard too many stories from friends, colleagues and members of my family that just makes me want to say this again. Over and over again.

1. Make sure you have connected your device

In order to format a storage drive, you first need to connect the device to a port found on your Mac. Afterwards, you need to turn the device on and check if the device appears in Finder.

Got a happy triggerfinger and already installed El Capitan but now you want to format your Mac’s internal drive? Don’t fret. You have to boot your machine in Recovery Mode in order to format everything.

To do so, you first need to start up your machine and press plus hold Command-R. A window called OS X Utilities should pop up. Don’t forget, if you format your internal drive everything will go poof and there’s no fix for this i.e. as you can’t bring people back from the dead, you can’t recover erased data such as files, apps, movies and such.

2. Start Disk Utility

You need to find Disk Utility to be able to format your drive. It can be found in Applications, in the Utilities section. Click to open it.

If you did everything in step 1, then you should see the image below.


Open Disk Utility – Repair or erase a disk using Disk Utility.

3. In Disk Utility, select your storage device

On the left side of Disk Utility, you’ll notice what storage devices are connected to your Mac. Just under, you’ll find the drive’s partitions. Select what device you need to format and click on the Erase button located at the top.


Be careful. If you notice that the Erase button is tarnished then it means that the drive you want to format is currently in use. Go back to the first step and follow it religiously.

4. Format and Name

If you’ve successfully completed the aforementioned steps, then a box will pop up and you will be required to enter a name for your formatted storage device.

This step is usually confusing and a lot of Mac users tend to seek help when they reach this step. It has a default selection called OS X Extended –  only Journaled. However, if you need a layer of security, you’ll want to pick OS X ExtendedJournaled and Encrypted. This means that your storage device will be encrypted.

If there’s no Encrypted option, it’s probably because the device you are currently formatting isn’t using the GUID Partition Map. If this is the case, there’s no need to worry. Just move forward to the next step and come back when you’ve completed it. Just repeat this step with the Encrypted option enabled.


Worth mentioning is the El-Capitan-only Case-Sensitive format. This means that you can have files or folders names with lowercase letters that are different, from a technical point of view, from those with capital letters. For example, FOLDER, Folder, and folder are different from each other and they can co-exist in the same, well, folder.

Don’t select ExFat or MS-DOS because they are for PCs. You are formatting external drive for Mac, not a PC, so just ignore them.

5. Selecting Scheme

The third, and final selection that you need to do in order to install El Capitan is called – Scheme. Select the GUID Partition Map and you are ready to install El Capitan on your Intel mac Machine.

Don’t even bother with the rest of the options. There are two options that don’t require your attention. Master Boot Record is aimed at Microsoft’s Windows, and the old-timer called Apple Partition-Map was designed for PowerPC Macs.


After you’re done, you can click on Erase, and the Disk Utility software will erase everything- data, pictures, movies, apps, projects and so on and so forth. It will start to reformat your storage drive and it will mount the device on your desktop.

This won’t take more than a twenty to thirty minutes – depending on your machine. Afterwards, your device has the green-light to install El Capitan on.

Don’t forget, and I can’t stress this enough, double, triple, quadruple check before you start the formatting external drive for Mac process. Enjoy!

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