APFS vs exFAT: Which to Use for a Mac External Drive

Use APFS if the drive will only ever be plugged into Macs. Use exFAT if it will ever be plugged into a Windows PC, a game console, a camera or a TV. That one question decides it for most people.

The rest of this page covers what actually differs, so you can check the table against your own case. The full five-format rundown, including Mac OS Extended, NTFS and FAT32, is in Best Format for a Mac External Drive.

What each format is

APFS (Apple File System) is the format every modern Mac uses for its own storage, and Disk Utility offers it first when you erase an external drive. exFAT is a Microsoft format that macOS, Windows, Linux, game consoles and most cameras can all read and write.

How they differ

Compatibility is the big one. A Mac-only drive formatted as exFAT works fine. An APFS drive plugged into a Windows PC shows up as unreadable and Windows offers to format it, which you must not accept if you have files on it. Linux needs extra drivers for APFS as well.

Time Machine needs APFS or Mac OS Extended on a local drive, so exFAT is out for backups.

Hidden files on exFAT. When a Mac writes to exFAT, it stores extra Mac metadata in companion files whose names start with ._. You will see them if you open the drive on Windows, and they are harmless. APFS doesn’t need them.

Encryption. Choose APFS (Encrypted) in Disk Utility to protect a drive with a password. The encryption is hardware-accelerated on Apple silicon Macs. A Windows PC can’t read it.

What happens if the drive is disconnected mid-write

APFS writes its metadata with copy-on-write, which helps keep the filesystem’s structure consistent after an interruption. exFAT has no journal, so a disconnect during a write can leave the directory structure inconsistent, and the damage can reach files other than the one being written.

That’s a real difference, but it has limits. APFS does not make an unplanned disconnect safe, because the file being written can still be lost or corrupted. Eject normally and keep a separate backup whichever format you pick. The risks are covered in Is Force Eject Safe? and Can Unplugging Your External Drive Damage It?.

SSD or hard drive?

APFS was designed with flash storage in mind and works well on SSDs. It also works on spinning hard drives, and it is the default Disk Utility offers on a modern Mac. If the drive needs to be read by a Mac running macOS older than 10.13 High Sierra, those Macs can’t read APFS and you should use Mac OS Extended (Journaled) instead.

How to format the drive

Changing between APFS and exFAT erases the drive. Copy your files somewhere else first.

1. Open Disk Utility (Applications > Utilities) and choose View > Show All Devices.
2. Select the physical drive at the top of the list, not the volume under it.
3. Click Erase, name the drive and pick the format: APFS, APFS (Encrypted) or ExFAT.
4. Choose GUID Partition Map as the scheme. Use Master Boot Record only if an older device, such as an older camera or TV, needs it.
5. Click Erase and wait for it to finish.

To see what a drive is currently formatted as, select it in Finder and press Command + I, or run diskutil info /Volumes/YourDriveName and look for File System Personality.

Whichever you pick, eject it properly

If you chose exFAT, ejecting properly matters most, since an interrupted write is the riskiest for it. When the Mac says a program is using the disk, how to eject an external hard drive on Mac covers what to try in order. For a Time Machine drive, see Time Machine won’t let you eject. If you are weighing a drive that came formatted for Windows, exFAT vs NTFS on Mac explains why macOS can’t write to NTFS by default.

Ejecta offers free diagnosis of what is holding a drive and paid actions to quit supported apps and retry the eject. It can’t guarantee that every drive will eject, and it doesn’t make an unplanned disconnect safe.