When an MP3 you exported from Audacity refuses to play, the usual problem is that the file was never properly written — not that your player is fussy. Audacity's own FAQ on MP3 export problems puts it bluntly: "Sometimes the exported MP3 may be invalid and only a few bytes in size; as a result, it will not play and give an error."
A few bytes. That is the tell. Before you reinstall anything or blame the player, look at the file size on disk — a real MP3 of a real recording is never that small, and a file that size will fail in every player you try.
What actually produces a few-byte MP3
The manual points at one setting: the Project Rate. From the same FAQ page: "The safest solution is to always set your Project Rate to 44100 Hz. Make a rule to check this before you export, because importing a file of some other sample rate may change the Project Rate to that rate."
Read the second half of that sentence twice, because it is the part nobody mentions. You probably never chose an unusual sample rate — an import chose it for you. Drop in a voice memo, a phone recording, or an old clip captured at some other rate, and the project follows the file. Nothing warns you at the moment it happens; the consequence only shows up at export time, possibly days later.
Audacity's Importing Audio page spells out what Project Rate governs, and the list includes the one that matters here: "when the audio is exported, it will be exported as a 44100 Hz file." Worth knowing: the same information box on the Audio Settings Preferences page lists only four consequences and leaves the export line out entirely. If that is the page you looked at, you would have no reason to connect Project Rate with a broken export at all.
There is a second, related mechanism the FAQ names: "LAME will automatically downsample from 44100 Hz to a lower sample rate at 56 kbps or lower, because low bit rates may give poor quality with higher sample rates." Keep the qualifier attached — that automatic downsampling is described for exports at 56 kbps or lower, not for every export.
One more piece of context. The MP3 Export Options dialog offers only three sample rates: 32000 Hz, 44100 Hz (the default), and 48000 Hz. A project whose rate was dragged somewhere else by an import is operating outside the short list the MP3 exporter was built around.
The fastest fix
- Open the track's rate. The sample rate of the audio on screen is shown in Hz on the Track Control Panel, above the mute and solo buttons.
- Set Project Rate to 44100 Hz in Audio Settings Preferences. This is the manual's stated "safest solution," and it is worth doing as a habit before every MP3 export rather than as a repair.
- If the track rate and the Project Rate disagree, resample first. For the case where exporting crashes, hangs, or takes a very long time, the FAQ's advice is: "Try resampling the track to your chosen Project Rate before exporting as MP3. To do this, select all the track by clicking in the Track Control Panel, then Tracks > Mix > Mix and Render." Doing it up front also removes the mismatch that caused the bad export.
- Export again with File > Export Audio, choosing MP3 from the Format dropdown.
Try it right here
Runs in your browser. Your file is not uploaded anywhere.
If you would rather not gamble on another export, take the lossless route the manual recommends anyway: export to WAV, which is not encoded by LAME at all and has nothing to go wrong at this stage, then convert that WAV to MP3 here. The converter above runs inside your browser tab — the audio is read from disk and encoded locally, so nothing is uploaded. Audacity's MP3 page makes the same argument for a different reason: "never do production work in MP3, instead work with a lossless format such as WAV, AIFF or FLAC and for final use then export to MP3." If you want the reverse direction later, MP3 to WAV is the same idea backwards.
Other causes, in order of likelihood
It plays, but far too fast. This is the same root cause wearing a different costume. The FAQ: "If the MP3 plays at the wrong speed (usually too fast), then the sample rate you exported it at is unsuitable for your player application. Once again, the safe solution is to always set your Project Rate to 44100 Hz."
It plays, but there is no sound. Check the gain slider before you re-export. The FAQ says to "make sure the -....+ Gain/Volume slider on the Track Control Panel (where the mute/solo buttons are) is set centrally at 'Gain/Volume: 0 db'. If this slider is over to left, it will reduce or kill the volume in the exported MP3."
The export was interrupted. Audacity treats the two buttons differently: "Stop button will halt the export where it is now, leaving the partially exported file in place," while "Cancel button will abort the export leaving no exported audio file." A file left behind by Stop is a partial file, and a partial file can behave exactly like a corrupt one.
The name says MP3 but the contents do not. Audacity warns when an extension does not match the format, and the manual's Windows example is precise: exporting as M4A (AAC) while typing "rhythms.mp3" produces a warning "because you would export a file that Windows would see as an MP3 but contained MP4 audio." The manual also advises you to "avoid periods (dots) in the file name, or you will have to add the extension such as .wav or .mp3 at the end of the name."
You are on Linux without LAME. The MP3 encoder is built in on two platforms only: "The software patent on LAME encoding library has expired, so now the LAME library for MP3 export is built-in with Audacity for Windows and Mac. Linux users will still need to download and install the free and recommended LAME third-party encoder to export MP3 files from Audacity."
How to tell it worked
Check the size on disk first — that single number separates "invalid and only a few bytes" from "a real file that a player is mishandling." For a sense of scale, the manual notes that the 128 kbps constant-bit-rate setting "gives you a known file size of about 1 MB per minute of mono or stereo audio." Audacity's default is not that setting, so treat it as a rough floor, not a target.
Then play it somewhere outside Audacity. And if the exported audio is missing a track, remember that preview is authoritative: "What you hear by previewing with playback prior to export is what you will get in the Exported audio file."
FAQ
Why is my exported MP3 only a few bytes? Audacity's FAQ ties invalid, few-byte MP3 exports to the Project Rate and tells you to always set it to 44100 Hz before exporting. The trap is that importing a file recorded at another sample rate may change the Project Rate to that rate without you asking.
Do I still need to install LAME for MP3 export? Not on Windows or Mac — the manual says LAME is now built-in on both. Linux users still need to download and install it separately. Most "install LAME first" tutorials you will find are describing the old situation.
What bit rate does Audacity export MP3 at by default? Two official pages disagree, so it is worth checking yourself. The MP3 Export Options page says "The default MP3 encoding options in Audacity are 170 - 210 kbps VBR (preset 'Standard')," while the MP3 export problems FAQ says "Audacity defaults to 128 kbps bit rate then remembers the last used bit rate if you change it." On the options page, 128 kbps is the default for the Constant bit rate mode specifically.
Why does my exported MP3 start with a short silence? That is the format, not a failed export. The manual: "MP3 files have a short silence at the beginning due to encoder delay. This is a limitation of the MP3 format." Audacity stores the exact length in the LAME Mp3 info tag and apps that read that tag strip it automatically; many apps do not. For sync work or loops the manual recommends WAV, FLAC or Ogg Vorbis instead.
Why is the exported MP3 much bigger than the file I imported? "This is because the bit rate you exported it at is higher than the bit rate of the original file," per the FAQ. It also warns that re-exporting at the original low bit rate degrades quality more than going higher. See our WAV to MP3 converter if you want to choose the output yourself, or browse all Clapr tools.
More export failures, sorted by symptom, live in the fix guides — including exporting MP3 from DaVinci Resolve. All Audacity behaviour above is quoted from the official Audacity Manual, checked 16 September 2026.
