Which Format Should You Choose For An External Drive?

Tech Tips– Most of us use some sort of external USB attached storage on a regular basis. It is important to keep in mind that media can be formatted in many different ways. Which filesystem you format an external drive with depends on the system(s) you plan to use it with. That said, there are many different filesystems to choose from


For Linux systems, the most common format is ext3 or ext4. But neither of those formats of disks can be natively read by your Mac. You can, with the use of the third party software such as “FUSE for Mac” or “extFS for Mac by Paragon Software“, read ext3 or ext4 disks. 


Our current Macs use disks with either the “Mac OS Extended” (HFS+) or the more modern “Apple File System” (APFS) filesystem.

You may be able to mount and read an HFS+ disk on your Linux system without additional software. Or maybe you will need to install some additional software. That depends on what was included in the installation. The same is true for APFS formatted disks – install apfs-fuse to read these. There is also a Paragon product for Linux that allows Apple disks to be mounted.

If you want to read either HFS+ or APFS disks on a Windows systems there is third party software you can get to do that. For HFS+ disks, install HFSExplorer, Paragon’s HFS+ for Windows, or Mediafour’s MacDrive. For APFS disks you can buy “APFS for Windows by Paragon Software“. The MacDrive package can also be purchased to read your macOS drives on a Windows system. The article “How to Read a Mac Formatted Drive in Windows: 6 Methods” covers these and more.


There are four different filesystems common to Windows – FAT16, FAT32, exFAT, and NTFS. The exFAT filesystem was created in 2006 for use with USB flash drives and SD cards, so it is not directly associated with a version of Windows.

Reading a drive formatted in any of these filesystems is easy on your Mac. Just plug the drive into your Mac and it will mount it. If the drive is formatted with FAT16, FAT32 or exFAT data can be read as well as written to the drive. If the drive is NTFS, data can only be read. If you want to write to an NTFS disk, then purchase either “Microsoft NTFS for Mac by Paragon Software” or “Microsoft NTFS for Mac by Tuxera“.

Making it easy

Usually, we know in advance where we are going to want to use an external drive. The simplest thing to do is to format the drive for use across as many systems as is possible. That means that for cross-platform compatibility, the best filesystem to use is FAT16, FAT32 or exFAT. Both FAT16 and FAT32 are readable on Windows, Mac, and Linux without any additional software needed.

The exFAT filesystem can be accessed by the Mac without additional software. Linux systems will need exfat-fuse, but that is easily installed.

Most Thumb drives or external disks come pre-formatted with FAT32. That makes them useable anywhere out of the box. The only reason you would want to go to exFAT is if the data you wanted to store on the media was larger than 4 GB. FAT32 has a limit of 4 GB on files. With exFAT, files can be up to 16 EB in length. That is 16 Exabytes or 1018 bytes (see “What Do Those Terms of Storage Mean?” for more on data storage) – sufficient large for any storage need.

Formatting Media on Your Mac

Screen Shot 2019-03-28 at 3.51.16 PM

External media can easily be formatted (these examples are on macOS High Sierra 10.13.6) on your Mac. Connect the drive to your Mac and open Disk Utility (Finder ==> Go ==> Utilities ==> Disk Utility). On the left side you will see all the connected external drives listed (red arrow in image above). Choose the one you want to format and then click on the Erase button (orange arrow in the image). NOTE: Formatting a disk permanently erases all data on the disk!

Screen Shot 2019-03-28 at 3.51.42 PM

This will drop down a window that allows you to give the drive a new name and pick the format you want used on the drive.

Screen Shot 2019-03-28 at 3.51.53 PMIf you click on the Format window, a drop down menu will appear giving you a list of the format options available to you. While the Mac lists MS-DOS (FAT) this is really FAT32. You also have the option of formatting a drive as exFAT.


Disk Filesystem Summary

Filesystem Native to Journaled[1] Max File Size When Introduced
ext3 Linux Yes 16 gigabytes 2001
ext4 Linux Yes 16 tebibytes 2008
FAT16B (BigFAT) DOS 3.1 of later No 4 gigabytes 1987
FAT32 Windows 95 or later No 4 gigabytes 1996
NTFS Windows NT or later Yes 16 exabytes 1993
exFAT Windows CE 6.0 No 16 exabytes 2006
HFS+ macOS 8.1 or later Yes (as of 2002) 8 exabytes 1998
APFS macOS High Sierra (10.13) or later No, more modern methods 8 exabytes 2017



  1. A journaling file system is a file system that keeps track of changes not yet committed to the file system’s main part by recording the intentions of such changes in a data structure known as a “journal”, which is usually a circular log. In the event of a system crash or power failure, such file systems can be brought back online more quickly with a lower likelihood of becoming corrupted.

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