Can't import m4a files to Audacity I have installed the latest version of ffmpeg (3.1.2) through homebrew, and I have gone to Preferences -> Libraries and located the ffmpeg library in Audacity (/usr/local/Cellar/ffmpeg/3.0.2/lib/libavutil.55.17.103.dylib).

Nothing happens when I load an m4a. If I import it through ⌘ + I it says "FFmpeg not found".
Audacity (as of v2.4.1) is not looking for libavutil.*.dylib, it needs ffmpeg.*.dylib. That is not installed by homebrew.
You will need to download ffmpeg.*.dylib by following the instructions at https://manual.audacityteam.org/man/installing_ffmpeg_for_mac.html
It should automatically install the ffmpeg library and configure the Audacity Preferences &gt; Library to:
/Library/Application Support/audacity/libs/ffmpeg.55.64bit.dylib
Then you will be able to import m4a audio files.