How to read and write ext4 on a Mac (2026)

Why a Mac can't open ext4

ext4 is the file system Linux formats its disks with – Ubuntu, Debian and Raspberry Pi OS among them. macOS reads APFS, Mac OS Extended, FAT and exFAT, and NTFS only for reading; it has no ext4 driver. Plug in a Linux disk and, when nothing on it is readable, macOS says “The disk you attached was not readable by this computer”, with Initialize, Ignore and Eject.

Don't click Initialize. It opens Disk Utility, where erasing the disk would format it for the Mac and delete everything on it. Choose Ignore or Eject; the files are still there. More in what “not readable” means for a Linux disk.

Everything that reads ext4 on a Mac adds a driver of some kind, and there are four kinds. A kernel extension runs inside macOS itself. A FUSE layer such as macFUSE runs the file system in an ordinary program. An FSKit app is a file system extension written against the framework Apple added in macOS 15.4 – the way Apple's own newer file systems run, outside the kernel. And a Linux virtual machine lets Linux read the disk and hands the files to the Mac.

Which kind matters more on macOS 27 than it used to, because macOS 27 runs only on Macs with Apple silicon. On those Macs a third-party kernel extension loads only after you lower the Mac's security policy to Reduced Security in Startup Security Utility, from Recovery. So on macOS 27, every kernel-extension route – Paragon's driver, macFUSE's kernel backend – asks that of every Mac. FSKit apps and virtual machines don't. More in ext4 without macFUSE or a kernel extension.

Every way, side by side

What each option reads and writes, what it does with the ext4 journal, whether it needs Reduced Security, and what it costs – as its maker describes it, with the page each row was checked on.

Every row was checked on its maker's own page on 2 November 2026. Apps change: if a row is out of date, tell us at apps@xfanta.com and we'll correct it.

Which one fits

• You want the files off a Linux disk, once. Any FSKit app that reads it will do. Extent and TuxKit read for free, with no time limit.
• You write to an ext4 USB drive or a Raspberry Pi card regularly. An FSKit app that writes through the journal, so a cable pulled mid-write leaves the disk consistent rather than half-changed.
• The disk is inside LVM, LUKS encryption or software RAID, or it's Btrfs, XFS or ZFS. anylinuxfs runs a small Linux and handles all of those. Luksmith unlocks LUKS; xlinuxfs reads and writes XFS and Btrfs. Which disks open with Extent, and which don't.
• You need Linux's own tools – e2fsck, mkfs.ext4, resize2fs. A Linux virtual machine, or the Linux machine the disk came from – though e2fsprogs runs on a Mac too: formatting a drive as ext4 on a Mac.
• A guide tells you to install ext4fuse. It only ever read ext4, its last change was in September 2020, and Homebrew marks its formula as Linux-only and deprecated as unmaintained. Guides that still recommend it predate everything else in the table.

Reading and writing ext4 with Extent

Extent is our own FSKit file system for ext2, ext3 and ext4. It needs macOS 27 or later on a Mac with Apple silicon.

1. 1

   Install Extent and open it

   It's free on the Mac App Store. Its window lists the Linux disks connected now and the ones it has seen before.

2. 2

   Turn on its file system extension, once

   System Settings › General › Login Items & Extensions › File System Extensions, and switch Extent on. The banner in Extent's window has a button that opens that pane. Use the File System Extensions row: on macOS 27, the switch under Extent's own row in the Extensions list can refuse to turn on.

3. 3

   Plug in the disk

   It mounts by itself, read-only, in the Finder and in every app, with the files where Linux left them. A disk image works too: File › Open Disk Image…, or drop the .img on the window.

4. 4

   To write, unlock writing and turn it on for that disk

   Writing is a one-time purchase under Extent › Unlock Writing…. Then turn on “Write to this disk” in the disk's details, eject the disk and connect it again: a file system is mounted either read-only or read-write.

5. 5

   Eject before you unplug

   In the Finder or in Extent's window, as with any disk. If the cable does come out mid-write, the journal brings the disk back consistent the next time it's connected.

If the disk doesn't appear, or stays read-only

• It isn't in the Finder or in Extent's window. The usual reason: the disk was connected before the extension was on, or while the Mac was starting up, and macOS doesn't offer it to Extent again. Eject it and connect it once more. Since version 1.0.2 Extent lists every Linux partition it can't open, with the reason.
• It's inside LVM, LUKS or software RAID, or it's Btrfs or XFS. Extent says so and can't open it; see “Which one fits” above and which disks Extent opens.
• Another ext4 driver took it. With Paragon's kernel extension or another FSKit app installed, macOS may hand the disk to that driver first. Extent's window names the driver that mounted the partition.
• Writing is on, and the disk still mounts read-only. Extent says why in a sentence: an ext2 or ext3 disk, ext4 without a journal, a feature it can't write yet – such as the case-insensitive folders of a Steam Deck's microSD card – damage Linux recorded, which wants e2fsck -f on Linux first, or an SD card's lock switch.

What Extent doesn't do

• It doesn't format or repair disks. Create ext4 with mkfs.ext4 – which runs on a Mac too – and repair it with e2fsck on Linux; when a disk needs a check, Extent gives you the command to copy.
• It doesn't open LVM, LUKS, software RAID, Btrfs, XFS or ZFS – anylinuxfs does.
• It writes only ext4 with a journal and extents, which is how Linux formats ext4 unless told otherwise. ext2, ext3 and ext4 with features it can't write yet stay read-only.
• It doesn't run on Intel Macs or before macOS 27: it is built on the FSKit API that macOS 27 introduced.

Frequently asked questions