When Apple Music will not convert your file to MP3

Apple's own support page ranks first for the Mac query and answers the happy path. This searcher already followed it and hit one of the failures Apple does not document: the menu item is greyed out, the import setting will not stick, the output went somewhere they cannot find, or the track is protected.

Nine times out of ten Create MP3 Version is greyed out for one of four reasons: nothing is selected in your Library, the selected track lives in iCloud and has not been downloaded to the Mac, the track is a protected Apple Music or old iTunes Store file that no software will convert, or the menu item is not greyed out at all and simply says Create AAC Version because your import setting still points at AAC. Fix that last one in Music > Settings > Files > Import Settings > Import Using: MP3 Encoder, then select a track and use File > Convert > Create MP3 Version. If the track is protected, stop there. If you would rather not put anything in your library at all, convert it in a browser tab instead and leave Music out of it.

The route that does work, in order

Apple's own support page covers this, but it skips the two steps people get wrong, so here it is with those included.

1. Open Music. In the sidebar click Library, then Songs. This matters more than it looks: in Listen Now, Browse or Radio, the entire Convert submenu stays dim because those views show Apple's catalogue, not your files.
2. Choose Music > Settings… (⌘,) on Ventura and later, or Music > Preferences… before that. On Mojave and earlier the app is still called iTunes and the settings live under General.
3. Go to the Files tab and click Import Settings….
4. Set Import Using to MP3 Encoder. Under Setting, the presets are Good Quality (128 kbps), High Quality (160 kbps) and Higher Quality (192 kbps); Custom… goes up to 320. Pick Higher Quality unless you have a reason not to — 320 against 192 covers why the top number is rarely worth the bytes.
5. Click OK, then close the Settings window completely. The File menu reads its wording from this setting, and leaving Settings open is the usual reason the menu still says AAC.
6. Select one or more songs, then File > Convert > Create MP3 Version.

Music writes a second copy and leaves the original exactly where it was. Nothing is replaced, which is why the library often looks like it has doubled afterwards.

Why it is greyed out

Work down this table. The symptom is usually enough to tell the causes apart.

To see the Kind column, right-click any column heading in Songs view and tick Kind. It is the fastest way to tell a plain AAC audio file from a Protected AAC audio file, and later it is how you find the MP3s you just made.

Why it converted more than you meant to

Two selections catch people out. Clicking an album's artwork in Albums view selects every track on it, and ⌘A in Songs view selects the entire library. Music will happily work through all of it, and because each converted copy keeps the same title, artist and album as the original, the library appears to have doubled rather than gained anything.

Sorting by Kind untangles it. MP3s show as MPEG audio file and the originals as AAC audio file, Apple Lossless audio file or Purchased AAC audio file. Select the rows you did not want and delete them; Music asks whether to move the files to the Trash, and the answer is yes, since the originals are the other rows.

There is no progress dialog for a large batch, only a small spinner near the top of the window. A few hundred tracks is a long job, not a quick one, because every file has to be decoded and re-encoded.

Where the converted file actually went

Select the new copy and press ⇧⌘R (File > Show in Finder). That is the definitive answer, and it beats guessing at paths.

The usual location on Catalina and later is ~/Music/Music/Media/Music/Artist/Album/. Under iTunes it was ~/Music/iTunes/iTunes Media/Music/. If Copy files to Music Media folder when adding to library is unticked in Settings > Files, the new file can land beside the original instead — another reason to let Finder tell you rather than assume.

To get the MP3 out of the library and into a folder you chose, drag the track from the Music window straight into a Finder window. That copies the file; it does not move it or remove it from the library.

Protected tracks: this one has no fix

Apple Music downloads are encrypted, and so are iTunes Store purchases from before 2009. Music refuses them with a message along the lines of:

Some of these files were not converted because you are not authorized to play them on this computer.

This is not a setting you have missed. The audio is not readable without the licence, so no converter can open it — not this Mac's Music app, not any website, and not the converter on this one. If you own the album on a CD, rip it. If you bought it from the iTunes Store after 2009 it is unprotected AAC and converts normally. Anything you only have because of an active subscription stays inside the subscription.

Converting without touching your library

If the file is a voice memo, a recording someone emailed you, or anything else you have no wish to import, the Music app is the wrong tool. Three alternatives, none of which adds a row to your library.

In a browser tab

The M4A to MP3 converter here is FFmpeg compiled to WebAssembly, running inside the page. The file is read off your own disk and never leaves the Mac; there is no server involved and no account. It also reads the file first and tells you what codec, length and bitrate it found, which is useful when you are not sure whether an .m4a holds AAC or Apple Lossless.

Two caveats worth knowing. The first visit downloads a 32 MB engine, cached for a year afterwards, so it is not the thing to do on a tethered phone connection. And M4A to MP3 can never be a stream copy — the AAC has to be decoded and re-encoded, which takes a real fraction of the recording's length. A one-hour interview is a coffee, not a click.

Terminal, for a whole folder

If you have Homebrew, brew install ffmpeg and then, in the folder:

for f in *.m4a; do ffmpeg -i "$f" -c:a libmp3lame -q:a 2 "${f%.m4a}.mp3"; done

-q:a 2 is variable bitrate averaging around 190 kbps. Use -b:a 192k instead if you want a fixed number for a device that is fussy about it.

GarageBand, which is already installed

Drag the file into an empty GarageBand project, then Share > Export Song to Disk and choose MP3. It works and it is free, but it is a lot of clicking for one file.

Two Mac routes that look promising and are not: QuickTime Player's File > Export As > Audio Only writes an .m4a, and Finder's Encode Selected Audio Files quick action offers Apple formats only. Neither will give you an MP3.

What the conversion costs you

M4A to MP3 is one lossy format decoded and re-compressed into another, so it cannot restore anything the original AAC encoder threw away, and it discards a little more of its own. At 192 kbps and above that second pass is inaudible to most listeners on most material, which is why the Higher Quality preset is the sensible default rather than Custom at 320. The detail is in does converting M4A to MP3 lose quality, and M4A vs MP3 is worth two minutes if you are not sure you need to convert at all — a modern Mac, iPhone, Android phone and every browser play M4A perfectly well. The reason to make an MP3 is nearly always a specific piece of software or hardware that demands one.