How to format USB on Mac: Formatting external drives, safely

8 min read

Ask any Apple fan what the worldwide market share of Windows vs. macOS is and you’ll probably get a response along the lines of “about 50/50.” In Apple-dominated spaces like design, you might get some people estimating that the number associated with Apple is even higher.

In reality, this couldn’t be further from the truth. With a worldwide market share of more than 85%, Windows beats macOS’ 10% by a significant amount. As frustrating as it might be, this is the main reason for why it shouldn’t be surprising that most device manufacturers still make their products with Windows in mind and we have to look up how to format an external hard drive on Mac.

Out of the box, USB flash drives may function unreliably or even fail to work on Macs at all. The reason? Mac and Windows each use different file systems.

After unboxing a new storage-based item, it’s a wise move to look into how to format a hard drive for Mac (or SD card, flash drive, etc.) to reduce the likelihood of unexpected corruption, data loss, or other performance issues. Read below to see what to do.

Format USB flash drive on Mac

Thanks to Disk Utility, the issue of how to format USB on Mac is fairly straightforward. Likewise, you can use this tool to format Micro SD cards, hard drives, and so on, getting your new device into the right condition. 

Note that formatting a drive means completely erasing it, so make sure you read our recommendations on how to back up and recover files below. 

  1. Plug the device into your Mac
  2. Go to Applications > Utilities and open Disk Utility
  3. Select the relevant device or drive in the left sidebar and click Erase
  4. Give the device a name and choose the desired format (more on that below)
  5. Click Erase to reformat the device

format usb mac

First of all, let’s cover the obvious point above: when you format USB drive on Mac, or any similar device for that matter, you need to erase everything that’s on it in order to do so. That’s not a problem if the device is new, but means you’ll need to take some precautionary measures if it’s not.

Second, the desired format will depend on the type of device you’re using. Commonly, macOS uses APFS and Windows uses NTFS (which is read-only on Mac). However, there are some differences even within the macOS ecosystem: 

  • If you’re looking at how to format SD card on Mac, you’ll want to go with ExFAT. 
  • If you’re trying to format flash drive on Mac or figure out how to format an external hard drive, you’ll likely want to go with APFS. 
  • If your macOS is older than High Sierra, stick with Mac OS X Extended because APFS is unavailable on old systems. 
  • When you format hard drive for Mac to be used in conjunction with Time Machine, you’ll also want to go with Mac OS X Extended, as Time Machine can’t use APFS directly and will offer to reformat it if you try to do so. 
  • Wondering how to format hard drive for Mac and Windows at the same time? FAT32 and ExFAT are the best options in this case.

Tip: If you’re trying to use external volumes that are formatted as NTFS on Mac, it won’t work unless you install iBoysoft NTFS for Mac, an app that unlocks read and write support for NTFS on Mac. 

iBoysoft NTFS for Mac

Always back up before formatting

Frequent backups are a must. An app like Get Backup Pro for Mac can help you quickly save your data before you format micro SD card or any other device, since it allows you to synchronize across different computers using mounted drives, in addition to simple copy, incremental, and bootable backups.

When you load up Get Backup Pro, you’ll be prompted to create a new project. Just give it a name, choose a destination for the backup and, if desired, set when backups should be triggered automatically.

get backup pro mac drive sd

While it’s certainly possible to back up your files with Time Machine, Get Backup Pro is a much better choice because it can reduce the size of your archives by up to 60% and allows you to recover your files on any machine (even if it doesn’t have the app installed).

Admittedly, it’s quite ironic that you need to back up data before you do anything, like format external hard drive for Mac, when it’s probably the very device you usually use for backing up. For that reason, you’ll want to own at least a couple of drives or disks to stay on the safe side.

Don’t forget that you shouldn’t always back up everything — you can go with the essentials. While Get Backup Pro lets you cherry-pick files and folders for backup, ChronoSync Express has quick shortcuts to back up or sync certain folders. If that’s what you want to do, check out ChronoSync’s setup assistant, it’s pretty straightforward. 


You can pick a task — let’s say, Folder Backup — pick your folder and backup destination (it could be an external volume), and ChronoSync Express will quickly create a bootable backup for you. We also love this app’s syncing feature, which is perfect for when you need to compare the contents of several folders or move just the select files to a backup folder. 

Recover lost data with no sweat

However careful you’re to back up your files, data loss is always a possibility. In fact, you can do everything right and still encounter disk errors or corrupted data. Perhaps your lost data is simply down to forgetting to back up immediately before you went to format flash drive on Mac!

Whatever the reason, an app like Disk Drill can be invaluable for recovering lost data. Here’s how to use Disk Drill to bring the deleted files back: 

  1. In Disk Drill, choose Data Recovery > Storage devices 
  2. Choose your volume from the list and click ‘Search for lost data’
  3. Once the scan is done, you can review all found items and recover only those you need, or click ‘Recover all’

disk drill recover

In the case of data recovery due to a formatting mishap, Disk Drill is a life-saver because it offers a double dose of assistance in that you can use it to:

  1. Locate files that you’ve deleted off your Mac because you assumed they were safely backed up on a drive that’s now inaccessible
  2. Recover files that you’ve deleted from the SD card or memory stick to make more space for new photos. 

Avoid the scourge of data loss forever

There are few things worse than losing your data, whether that happens because your drive or SD card has become corrupted or because you forgot to back up before you decided to format hard drive for Mac. Fortunately, as we’ve seen above, there are ways to get your hands on data that initially seems to be unrecoverable!

Of course, it’s even better if you never get to that spot in the first place, and doing regular backups is the best way to do that. Macs offer a built-in option to do this using Time Machine or iCloud, but the former isn’t compatible with every type of storage device and the latter has a monthly cost associated with it that you might prefer to avoid. That’s why so many people end up looking at how to format external hard drive on Mac, or use other devices like USB sticks.

Using backup software in conjunction with an app that’s capable of recovering lost data from USB flash drives, SD cards, and so on, covers most of your bases when it comes to avoiding catastrophic data loss. 

You might also want to add a cloud solution like Google Drive or Dropbox (both of which have free plans) into the mix as an extra layer of protection in case of fire, flood, theft, or something as simple as an unexpected error when you format the flash drive on Mac. There’s no such thing as being too prepared.

Get Backup Pro, ChronoSync Express, Disk Drill, as well as some great tools for cloud storage tasks are available to you on a free trial via Setapp, a productivity service with over 200 tools and utilities to solve any problem. Now that we’ve ensured you know the basics, it’s time to answer some of the most common questions on the topic. 


What format should a USB be for Mac?

APFS is the original default file format used on macOS, so it’s your best bet for formatting a USB. However, you should note that APFS is not compatible with some older versions of macOS — for those you might need to use Mac OS X Extended or other formats. 

How to change read only USB Mac without formatting?

Try iBoysoft NTFS for Mac. Most often, read-only volumes are formatted as NTFS, which is originally a Windows format. The iBoysoft app unlocks the write support for NTFS drives. 

If your USB is not formatted as NTFS, yet it’s read-only, try changing permissions (right-click the USB in Finder > Get Info > Sharing & Permissions > change to Read & Write). 

How to format a USB drive for both Mac and Windows?

FAT32 is commonly believed to be an optimal file format that can work both on macOS and Windows. That’s true, but note that it can only handle files under 4GB. If you need more, try ExFAT. 

How to format a USB on Mac for FAT32?

To make a USB formatted as FAT32, open Disk Utility and choose your USB, then click Erase. Under Format, choose MS-DOS (FAT). That’s it!

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