CDJ ERROR E-8304 / E-8305:
UNSUPPORTED FILE FORMAT

Officially documented. AlphaTheta publish an error code article for each player, and seven of them carry this pair. On every one, the two codes share a single row, a single cause and a single action.

E-8304

UNSUPPORTED FILE FORMAT. The cause AlphaTheta give: music files that cannot be played with the unit are loaded. The action they give: load music files in a format the unit supports.

E-8305

UNSUPPORTED FILE FORMAT. The same row, the same cause and the same action. In AlphaTheta's user documentation these two numbers are one condition, not two.

The seven players with a published article for this pair are the CDJ-3000, CDJ-3000X, XDJ-RX3, XDJ-AZ, XDJ-XZ, OPUS-QUAD and OMNIS-DUO. If your deck is not one of those, the code very probably means the same thing, but we are not going to tell you AlphaTheta documented it for a player where they did not.

This part is ours, not AlphaTheta's. It is the order we would work in, and every step is reversible.

• Load a different track from the same drive. If it plays, the drive mounted, the database read and the browser worked. That is most of your rig proving itself in one move.
• One track fails, the rest play. Play around it. That file is in a format this deck does not take, and nothing else about your night has changed.
• Several fail and they have something in common. Same source, same folder, same file extension, same day you bought them. That pattern is the answer: it is a group of files, still not the drive.
• Every single track fails with this code. Try one of them on another deck in the booth if there is one. If it plays there, you have a player that does not decode your format, and there is nothing to repair.
• Nothing loads and there is no format message on screen. Then you are not looking at this error, and the drive or the database is genuinely in question. Start there instead.

Do not format the drive because this code appeared. Read what the message is actually about. Every action AlphaTheta publish for these two codes is about the compatibility of the file that was loaded. None of them asks you to erase anything.

Do not rebuild the library either, not until something has actually pointed at the library. A healthy drive can hold a file a particular player cannot decode. Format the drive, copy the same file back, and the deck refuses it in exactly the same way, except now the rest of your set is gone too.

This is not an argument that formatting is never right. It is a specific instruction about order: a format is a repair for a drive or a database problem, and neither of those has been established yet. Establish it first. If the drive really is the problem, the format guide is there and it will still be there in ten minutes.

Related: Get files off a drive first The player will not read the USB

Scope first, because it matters here. What follows is documented for the CDJ-3000X and for no other player. It comes from AlphaTheta's own service manual for that unit, Order No. DRT2037, section 4.2.

In that document the two codes are separated. E-8304 is recorded as a decoding error, with the loaded audio file in a format the unit does not support. E-8305 is recorded more plainly as a format that is not supported.

Why we are telling you and why it changes nothing. It is a difference in how AlphaTheta document the unit at two levels, not a difference in what has gone wrong for you. The user-facing article for the same CDJ-3000X puts both numbers in one row with one action. There is no second procedure hiding behind the higher number, and any page that gives you two different fixes for these two codes is inventing the second one.

We have not found an equivalent service document for any other player, so we are not extending this to one.

These sit next to each other in the numbering and they are different problems.

E-8302

CANNOT PLAY TRACK. The player cannot read the track data at all. AlphaTheta's cause is a file that may be corrupted, and their action is to try it on another player and re-import it. That is damage. Full fix →

E-8304 / E-8305

UNSUPPORTED FILE FORMAT. The player can see the file perfectly well and does not speak that format. That is compatibility. The file is not damaged.

Damage and compatibility need different responses, which is why the deck gives them different numbers. Read the number.

On older gear the numbering is not the same numbering. The CDJ-2000's own Operating Instructions, document DRB1475, give E-8301, E-8302 and E-8303 all as PLAYER ERROR, with their own cause and their own action. If that is the deck in front of you, its page carries the detail.

Because what a player can decode is a property of that player, and it can change with a firmware version.

A documented example. The XDJ-XZ gained FLAC playback in firmware 1.10. The same FLAC file, the same drive, two XDJ-XZ units on different firmware: one plays it and one reports an unsupported format. Nothing is wrong with the file in either case.

That is one model and one format, and we are naming it because it is documented rather than because it is the general rule. We are not going to hand you a compatibility matrix for every player and every format, because AlphaTheta do not publish one and the matrix would be ours rather than theirs.

Related: Firmware versions and what they fixed

• Look up the supported file formats for the actual player you will be on. Each model publishes its own list in its own Operating Instructions, and that list is the answer for that deck. A format one player takes is not a promise about the next one.
• Keep a version of the track the deck accepts. Re-encoding is worth doing when a specific format is the blocker, and it is not a ritual to perform on a whole library.
• Re-export from rekordbox after you change or replace a file, so the database and the audio agree.
• Check the player firmware when you have access to the booth, since decoding support is added in firmware and an un-updated unit is behind its own specification sheet.
• Test on the real gear whenever you can get near it. A soundcheck answers this question in thirty seconds and nothing else does.

Related: The full prevention system rekordbox export failed

AlphaTheta do not publish a table showing which older players refuse which file variants. There is no document that says "this deck rejects that flavour of WAV", and we have looked.

So this page does not contain one. We can tell you what the codes mean, which players AlphaTheta document them on, and what not to do while you find out. We cannot tell you in advance which of your files a given deck will refuse, and a page that claims it can is guessing on your behalf.

If you hit this and worked out exactly what the file was, tell us. That is how this section gets shorter.