How To Erase and Reformat A New Drive For Your Mac

Hi, this is Gary with MacMost.com. Let me show you what you need to do when you get a new external drive for your Mac.

So whether you're getting a rather large spinning hard drive, a smaller spinning drive, or maybe a Flash Drive, or maybe even a USB Thumb Drive you probably want to reformat the drive before you use it on your Mac. The reason is most drives you get in the store are going to be formatted for Windows. You want to format it specifically for Mac. 

As an example here I'm going to use this little flash drive. But it is the same process even if it's a big hard disk drive that you're attaching. The first thing you want to do is connect it to your Mac. Then you want to look for it in the Finder. Now, if you don't have a Finder window currently open switch to the Finder and one should open or go to File, New Finder Window. Then look for the drive in the left sidebar. In macOS Tahoe it should be under Locations. So you want to make sure you have that section expanded. Here I've got a few external drives and there's my USB Drive that I just inserted. So, I'm going to select it here and you can see that it's empty. 

Now even if it is empty and it looks like it is ready to use you do want to reformat it. Not only is it probably formatted for Windows but there could be a bunch of files on here. Sometimes they like to put a bunch of like Windows utilities and things on it. You want to erase it. The problem is, even with it selected here on the left and you're viewing it you won't find any option here on the Toolbar or in the Menus to erase or format the drive. It's there!. You just need to know where to look.

The place to look is the Context Menu. The Context menu is what you get when you Control Click, right click with a mouse, or two-finger click with the trackpad, on the item here, in this case the drive in the sidebar, and this is the Context Menu. You'll find Erase Disk right here. Select that and now this is what lets you reformat the Drive. Notice here it was formatted ExFat, the Windows format. So it is a good thing we are reformatting this drive. I'm going to choose instead the modern Mac format, APFS. When you select that then you get a few more options. 

The reason to use APFS is it's the modern system since 2017. You'll also find listed in macOS Extended which is the older system. But 2017 isn't the cutoff for hardware. You could easily have a 2013 or 2012 etc., Mac as long as it's using an operating system from 2017 or later, High Sierra or newer then it can use APFS. Unless you're running very old Legacy hardware and software, APFS is the right choice to make. You may hear people say, Oh, if it's a spinning drive then use HFS Plus. But there's no reason to do that. APFS works just as well, if not better, on a spinning drive. It was only very early on in the first year that you may have wanted to stick with HFS Plus. So, since it's not 2017 anymore APFS is the right choice.

Now there is one good reason to choose ExFAT instead. That's if this drive is being used as a transport drive, a way to get large files from your Mac to Windows and vice versa. We don't have as much need for transport drives anymore because there is good file sharing between systems on local networks and good file sharing across the internet using Cloud Systems now. But if you are creating a transport drive then ExFAT is probably your choice. I would recommend to only use that drive for transport. Don't use it for storage. If you need a transport drive have that be a separate drive from a drive that you actually store Mac files on and work with them on your Mac. So ExFAT will be the choice there.  

There's also the much older MS DOS FAT format if you need to be compatible with very old Windows machines. But for the vast majority of uses on your Mac, you're going to want APFS. It's important to note that if you do format the drive as ExFAT, then it won't work for certain things on your Mac. Certain kinds of files, like library files or the Photos App or iMovie or Final Cut Pro, you can't save those on an ExFAT drive, and other things may not work or may not work as expected. For instance, Spotlight won't work as well or may not work at all on ExFAT Drive. You also you would be missing some anti-corruption features that APFS has that ExFAT doesn't and security features like being able to encrypt it. So there are a ton of good reasons to only use ExFAT if you need something as a temporary transport drive between Mac and Windows. 

You also have a few other options here. Case Sensitive is one option. But you probably already know if you need that. You're a developer who's working on something where you need case sensitive drives. But the Encrypted option is actually a good one. When you select that then you get to enter a password and verify the password. Now you may think you need a password every time you connect that drive to your Mac. But your Mac's Password Keychain will offer to remember it for you and make it automatic. But if you then take that Drive to somebody else's Mac you'll need that password. But the reason to use an encryption is if you think there's any chance that this drive could get lost or stolen. Which is probably the case for most people. It could end up somewhere out of your control. Anybody can read the files on that drive. But with it encrypted they would need the password. It's not simply locking the drive, like they need to get past the lock to see the files. It's encrypting the files using that password making it nearly impossible for anybody else to get access to them without the password. That includes you! If you encrypted the drive and you don't save it in your Mac"s Keychain and you don't remember the password you won't be able to access those files later on either. So, make sure you have the password saved in your Password Manager and perhaps written down and stored safely somewhere as well so that you never run into that situation. 

There's another reason to use encrypted even though you don't think you may lose the drive anytime soon. That is when it's encrypted, when you erase the drive again all of the encrypted bits are now useless. So you've basically securely erased the drive just by erasing it. But if you erase a drive that wasn't encrypted then parts of files may still exist on that drive until they're overwritten as you use it again. So using the encrypted option isn't just secure for now, but could help security years from now when you use the drive for something else. 

So we also have the chance here to change the name of that drive. So I'll do so like that. Change it to whatever you want. Enter in your Password there or decide you don't want it encrypted. Then click Erase and then it will erase the drive, disappear from here and then reappear once the formatting is done.

There is one other way to get to this Context Menu. If you like you could go to the top level of your Mac, the computer level here. Then you'll see all the drives attached including this one and you can Control click, right click, or two-finger click and get to the same Erase Disk Utility. 

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There also is another way to erase and reformat the drive. That's to use the Disk Utility App that's on your Mac. When you run that you'll see your drives here in the left sidebar. Now if you select this drive and then you use the button here at the top, Erase, one of the things you'll notice is you don't have as many options. In fact under Format you'll notice you can't actually even switch formats. I only have APFS here. If the drive was ExFAT it would only present me with ExFAT here as my option. That's because I don't actually have the drive selected. I've just got the Volume on that drive. A drive can have multiple volumes, but with typical use you would just have the one. So in order to actually see the drive and be able to reformat it you want to go to View and switch from Show Only Volumes to Show All the Devices. Notice when I do that everything expands. You can see how I just had that volume selected there. I can, instead, select the drive itself which usually will show the name of the manufacturer of the drive. Select that and now when I click Erase I have all the options. They are all in this one format list here. So you see APFS, then Encrypted, Case Sensitive, and Case Sensitive Encrypted, for instance. You'll see other formats as well as ExFat here. So this is how you would reformat using Disk Utility. It just shows you another option here but for almost all uses today you would stick with GUID and then you can erase the drive with a new name here. If you select APFS Encrypted it's going to ask you for a password and to verify. 

Now do note that if you're buying a drive and plan to use it for Time Machine you don't actually have to worry about any of this. When you set it up it's going to format it for you. So to summarize all you need to do when you get a new external drive for your Mac is to find it in the left Sidebar of the Finder window. Control Click on it. Select Erase Disk. Choose APFS. Choose Encrypted and set a password for it and make sure you don't forget that password. Then Erase the disk that way. Then it's ready for use. I hope you found this useful. Thanks for watching.