Mount Ext4 on El Capitan
Try using ext4fuse.

ext4fuse This is a read-only implementation of ext4 for FUSE. The main reason this exists is to be able to read linux partitions from OSX. However, it should work on top of any FUSE implementation.

Basic usage, where N and M in /dev/diskNsM are the disk and partition numbers (such as 7 and 1) of your Ext4 (&quot;Linux&quot;) data. You can find these appropriate numbers for your machine in OS X' Disk Utility or by running diskutil list on the command line.
mkdir -p &quot;$HOME/tmp/my-linux-mount&quot;
ext4fuse &quot;/dev/diskNsM&quot; &quot;$HOME/tmp/my-linux-mount&quot;

On macOS Sierra the option -o allow_other is needed, as in:
ext4fuse /dev/diskNsM $HOME/tmp/my-linux-mount -o allow_other


Install both ext4fuse and osxfuse using Homebrew.
brew cask install osxfuse
brew install ext4fuse

According to the docs, you might also have to add &lt;your user&gt; to the operator group. Here using whoami to find your current username.
sudo dscl . append /Groups/operator GroupMembership &quot;$(whoami)&quot;

See also the fix for problems clicking &quot;allow&quot; for the &quot;System Extension Blocked&quot; message for osxfuse, and the osxfuse docs for mount options, such as allow_other and defer_permissions.