To format a USB drive on a Mac, open Disk Utility, choose View > Show All Devices, and select the USB drive. Click Erase, then pick a format. Choose ExFAT if you'll use the drive on both Mac and Windows, or APFS if it stays on Macs.
Choose MS-DOS (FAT) for a drive of 32 GB or less that a TV or car stereo needs as FAT32. Set the Scheme to GUID Partition Map, name the drive, and click Erase. Formatting deletes everything, so back up first.
Key Takeaways
- Disk Utility is the built-in tool for formatting USB drives on a Mac.
- ExFAT is the best all-round choice for a drive shared between Mac and Windows.
- APFS is Apple's default format and suits drives used only with Macs.
- Select the whole device, not just its volume, so you can set the partition scheme.
- Terminal's
diskutilcommand does the same job and helps when Disk Utility gets stuck.
Which Format Should You Choose on a Mac?
Choose the format based on which devices will use the drive. Apple explains each option in its guide to Disk Utility file system formats.
| Format | Best for | Works with | Keep in mind |
|---|---|---|---|
| APFS | Mac-only drives, especially SSDs | macOS 10.13 or later | Windows can't read it natively |
| APFS (Encrypted) | Private files on a Mac-only drive | macOS 10.13 or later | You need the password to open it |
| Mac OS Extended (Journaled) | Older Macs and macOS bootable installers | Macs | Apple requires it for startup disks on macOS Sierra 10.12 or earlier |
| ExFAT | Sharing between Mac and Windows, drives over 32 GB | Mac, Windows, and many newer devices | No journaling |
| MS-DOS (FAT) | Older devices that need FAT32, drives of 32 GB or less | Almost every computer and device | No single file of 4 GiB or larger |
Not sure between the Windows formats? Our exFAT vs NTFS guide explains why exFAT usually wins for portable drives.
How to Format a USB Drive With Disk Utility
Disk Utility is the most reliable way to format a USB drive on any recent Mac. These steps follow Apple's guide to erasing and reformatting a storage device.
- Connect the USB drive to your Mac.
- Open Disk Utility from Applications > Utilities, or search for it with Spotlight.
- Choose View > Show All Devices.
- In the sidebar, select the USB drive at the top of its hierarchy, not the indented volume below it.
- Click Erase in the toolbar.
- Click the Scheme menu and choose GUID Partition Map.
- Click the Format menu and choose a format from the table above.
- Type a name for the drive.
- Click Erase, then Done.
If the Scheme menu is missing, you selected a volume instead of the device. Go back and select the top item.
GUID Partition Map or Master Boot Record?
Use GUID Partition Map for almost every USB drive. Apple's erase guide uses it, and modern Macs and Windows PCs read it.
Master Boot Record is the older scheme. Choose it only when an older PC, TV, or car stereo won't recognize a GUID-formatted drive, often together with MS-DOS (FAT).
Format a USB Drive From Finder
Recent versions of macOS can erase a drive without opening Disk Utility. Apple describes this shortcut in Connect and use other storage devices with Mac.
- Open a Finder window and Control-click the USB drive in the sidebar.
- Choose Erase Disk.
- Enter a new name if you want one.
- Choose a file system format and click Erase.
If you don't see Erase Disk, your macOS version doesn't include it. Use Disk Utility instead.
Format a USB Drive With Terminal
Terminal's diskutil command formats a drive in one line. It's useful when Disk Utility shows an error or you need a specific scheme.
First, list your disks and note the USB drive's identifier, such as disk4:
diskutil listThen erase it. This example formats the drive as ExFAT with a GUID partition map:
diskutil eraseDisk ExFAT MYUSB GPT /dev/disk4- Swap
ExFATforAPFSfor a Mac-only drive, orFAT32for an MS-DOS (FAT) drive. - Swap
GPTforMBRif an older device needs a Master Boot Record. - Replace
MYUSBwith your drive name.
The wrong identifier erases the wrong disk. Compare the size shown by diskutil list before you press Return.
How to Format a USB Drive on Mac for Windows
To use a USB drive on both Mac and Windows, format it as ExFAT. Apple's guide to formatting a disk for Windows computers gives two rules:
- ExFAT for drives over 32 GB.
- MS-DOS (FAT) for drives of 32 GB or less.
Apple also limits Windows-compatible volume names to 11 characters. If a device specifically needs FAT32 on a larger drive, see our guide on how to format a USB to FAT32.
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Some uses have their own format rules. Check these before you erase.
| Use | Format | Why |
|---|---|---|
| macOS bootable installer | Mac OS Extended (Journaled) | Apple's installer tool erases the drive to this format |
| External Mac startup disk | APFS | Apple recommends APFS, especially for SSDs |
| iPhone or iPad storage | ExFAT or APFS, single partition | Apple requires one data partition in a supported format |
| TV, car stereo, or firmware update | MS-DOS (FAT) or ExFAT | Follow the device manual |
| PS5 or Xbox game storage | Let the console format it | Consoles erase and set up their own format |
Moving photos straight from your phone? See how to transfer photos from iPhone to a flash drive.
Troubleshooting Mac Formatting Problems
Most formatting errors on a Mac come from the wrong selection, an app using the drive, or a connection problem.
| Problem | Fix |
|---|---|
| No Scheme menu in the Erase dialog | Select the device at the top of the sidebar, not the volume |
| Erase fails because the disk couldn't be unmounted | Quit apps using the drive, then try again or use diskutil
|
| Drive isn't listed in Disk Utility | Choose View > Show All Devices, then check the cable and port |
| Security Options button is missing | Apple only offers secure erase on some storage devices |
| Can't copy files to the drive | The drive may be NTFS, which is read-only on a Mac. Reformat to ExFAT after backing up. |
If the drive won't appear at all, follow our guide to a USB flash drive not showing up.
Common Mistakes to Avoid
- Erasing the volume instead of the device. You lose control of the partition scheme.
- Choosing APFS for a shared drive. Windows PCs can't read it without extra software.
- Choosing MS-DOS (FAT) for video files. Files of 4 GiB or larger won't copy.
- Using a long name on a Windows-compatible drive. Apple limits these names to 11 characters.
- Formatting without a backup. Erasing deletes every file on the drive.
Frequently Asked Questions
How do I format a Mac USB drive to use it on Windows?
Open Disk Utility, select the drive, click Erase, and choose ExFAT. Apple recommends ExFAT for Windows drives over 32 GB and MS-DOS (FAT) for drives of 32 GB or less. Keep the name to 11 characters. The drive then works for read and write on both systems.
Can I format a USB drive to FAT32 on a Mac?
Yes. In Disk Utility, FAT32 appears as MS-DOS (FAT). Apple recommends it for drives of 32 GB or less. For a larger drive that must be FAT32, use Terminal with diskutil eraseDisk FAT32. Remember that FAT32 can't store a single file of 4 GiB or larger.
How do I see what format a USB drive is on a Mac?
Select the drive in Disk Utility. The format, such as ExFAT or APFS, appears under the name at the top. You can also select the drive in Finder and choose File > Get Info. The Format line shows the file system.
What is the best format for a USB drive on Mac?
ExFAT is best when the drive moves between Mac and Windows. APFS is best for a drive used only with Macs, because it's Apple's default and supports encryption. Use MS-DOS (FAT) only when an older device requires FAT32.
Does formatting a USB drive on Mac erase everything?
Yes. Erasing creates a new, empty file system and removes access to every file on the drive. Copy anything you want to keep to another location first. Apple's Disk Utility guide tells you to copy files to another device before erasing.
Final Thoughts
Knowing how to format a USB drive on Mac mostly comes down to picking the right format. Use ExFAT for drives shared with Windows, APFS for Mac-only drives, and MS-DOS (FAT) only for older devices.
Disk Utility handles all three in under a minute, and Terminal's diskutil is there when you need more control.
