An iPhone voice memo won't open on Android, in Audacity, or on older players because it's saved as .M4A — an AAC-based format some apps don't support. Converting the M4A to MP3 makes it play and edit almost anywhere, and you can do it in your browser without uploading the recording.
Why won't my M4A voice memo open?
iPhones save Voice Memos as .M4A (AAC audio in an MP4 container). MP3 is universal; M4A isn't — some Android apps, older media players, car stereos, and audio editors like Audacity (without the right add-on) can't open it. The recording itself is fine; the format just isn't recognised.
The fix: convert M4A to MP3
Convert M4A to MP3 and it opens on Android, in Audacity, in transcription tools, and on virtually any player. It runs in your browser, so the recording isn't uploaded — which matters for private notes, interviews, and meetings.
Is there a quality loss?
Both M4A and MP3 are lossy, so converting re-encodes once — but at a reasonable bitrate it's inaudible for speech, and voice memos are speech. Quality is rarely a concern here; if you want the details, see why does my converted audio sound worse.
Editing a voice memo?
If you're trimming an interview or cleaning up a lecture, convert to MP3 first so Audacity and other editors open it reliably, then edit from there. Keep the original M4A as a backup until you're done.
Convert privately in your browser
M4A to MP3 runs on your device — nothing uploaded. Other Apple/AAC audio that won't open? AAC to MP3. For the general approach, see why won't my video or audio file play.