QUESTIONS & FIXES FROM THE BOOTH

Yes. No account and no paywall, ever. If it saves your gig you can buy us a coffee, but only after you are safe.

The most common causes, in order: the drive is formatted as NTFS or exFAT instead of FAT32; the partition map is GPT (we recommend MBR); the rekordbox database on the drive is corrupt (often from an unsafe eject); or the drive hardware is failing. You have already reseated it and tried the other player, so start from the file system: most "dead" drives are a wrong format, a GPT map or a corrupt database, not dead hardware.

E-8302 reads "CANNOT PLAY TRACK": the player cannot read the track data on the drive, in most cases a corrupt rekordbox export or a wrong file system. AlphaTheta documents the code that way on the CDJ-3000, CDJ-3000X, XDJ-RX3, XDJ-AZ, XDJ-XZ, OPUS-QUAD and OMNIS-DUO. Older gear can differ, and the CDJ-2000 is the documented case: its own Operating Instructions give E-8301, E-8302 and E-8303 all as PLAYER ERROR, with a different cause and a different action. With a laptop you can usually fix it on-site: re-export fresh from rekordbox, or, once everything on the drive that exists nowhere else is copied off, reformat FAT32/MBR and re-export. Never format a drive that still holds your only copy of anything.

FAT32 file system, MBR (Master Boot Record) partition scheme. On Mac: Disk Utility → Show All Devices → select the drive (not the volume) → Erase → MS-DOS (FAT) + Master Boot Record. On Windows the built-in Format dialog only offers FAT32 up to 32 GB; for a 64 GB drive use the free guiformat tool, the full walkthrough is linked below. Use a quality 32-64 GB drive.

FAT32, unless you know every player you will touch reads exFAT. FAT32 works on every rekordbox-era Pioneer DJ and AlphaTheta player, old and new. exFAT is only read by newer units on recent firmware, so a drive that works on a CDJ-3000 can be refused by the CDJ-2000NXS2 in the next booth. FAT32 is the format that never surprises you.

Yes. CDJs can play plain audio files from a FAT32 USB via the FOLDER view. You lose cues, grids, playlists, Sync and Quantize, but you keep the gig. That is the core of our critical-path rescue.

First work out which half is broken, because they are two different problems. If the PLAYERS cannot see each other, AlphaTheta give four checks and the player number leads: no two decks on the same number, the LAN cable in the LINK terminal, the switching hub powered on, and unnecessary devices off the hub. If the players link and REKORDBOX never shows a LINK button, it is the computer, and the first cause is not a fault at all: PRO DJ LINK works in EXPORT mode and not in PERFORMANCE mode.

Not on the front panel. A controller is your computer's sound card as well as its mixer, so AlphaTheta start in the software every time: open Preferences, Audio, and check the controller is the selected audio device, with master and headphones pointed at its own outputs. Then be careful about the driver step, because it is not the same on every unit: AlphaTheta publish two different procedures, and on a DDJ-FLX4 under Windows there is no driver at all to reinstall.

Not first. AlphaTheta's own documented cause for that symptom on Windows is the display adapter driver, not rekordbox itself: open Device Manager, expand display Adapter, right click the adapter you use and update its driver, and go to the Intel, NVIDIA or AMD download centre if that changes nothing. It is believable once you see why. rekordbox draws scrolling waveforms on every deck continuously, which is a graphics job, so a display driver that cannot keep up takes the whole application down at the moment it draws the first screen. Reinstall only after the driver is current.

Check microphone access first. Serato publish this as a known issue on Windows 10 and 11: Serato DJ Pro or Lite outputs no audio, or will not connect to the hardware, when the application is not allowed to reach the computer's microphone. It is a Windows privacy setting, not the audio device and not the driver. Start, type Microphone privacy settings, switch on access for apps and, further down, for desktop apps, then restart Serato. Only after that go through the ordinary no-sound order.

Ask what the WiFi did a moment before. Serato publish it as a known issue on macOS with DVS hardware: switching WiFi from off to on during playback causes a dropout followed by large latency, and resetting the audio buffer does not help. The only reset is to reconnect the hardware. The prevention is the useful part: turn WiFi off before you open Serato and leave it off for the set.

First confirm it is a dropout: Serato's USB dropout indicator lights when audio cannot be fed to the bus in time. Then the procedure depends on the platform. On a Mac, Serato give six settings in order, ending with the other USB port. On Windows, they start with the processor and the buffer size, then LatencyMon to name the driver at fault, and they document that many newer laptops, Surface and Dell among them, hide the High Performance power plan entirely, with a registry change to reveal it.

Serato's own list is four items: drivers from the maker's site, the controller plugged straight into the computer and not a hub, every USB port tried, and other USB devices disconnected. Then inMusic, who make the Denon DJ, Rane and Numark units, publish one troubleshooting article for all of them, with three things Serato's list does not carry: a wall outlet rather than a power strip, a venue that may need a power conditioner, and a direct USB-B to USB-C cable rather than an adapter. Plus Computer Mode on standalone units and MIDI Studio on a Mac.

Not if you can wait. Serato separate a crash, where the software quits, from a hang, where it freezes and stays open, and their advice for a hang is to let it crash on its own, because a forced quit throws away the crash log that says why. Then five steps in their order, and the one to do first is the internal-mode test: launch with no controller, load a track that works, and you know in a minute whether the hardware is the cause.

Because streaming tracks do not export. rekordbox publish it in one sentence: tracks from a streaming service cannot be exported to a USB storage device or SD memory card, on any service and any plan. Beatport Streaming is the one service usable in EXPORT mode, and even there playback is not possible with LINK EXPORT, so the tracks can sit in your playlists and still never leave the laptop. If the set is going onto a drive for the club's players, every track on it has to be a file you own.

Depends on the service and the plan, and the answers are all different. TIDAL: never, in rekordbox's own words. SoundCloud Go+: never. SoundCloud DJ: yes, but stored tracks are deleted after thirty days without a connection, and logging in online after twenty days resets that clock. Beatport: yes, and only on the Professional subscription, which is the only one with the offline locker. Recording is closed on every service. Assume the booth has no signal and check the plan before the gig.

Denon DJ document the cause: a conflicting Microsoft Visual C++ Redistributable already on the Windows machine. The fix is to uninstall a specific pair in Add or Remove Programs, both the x64 and the x86 entry, and run the installer again, which puts its own copy back. The pair is not the same for every model: Visual C++ 2012 for the Prime 2, Prime 4 and Prime 4+, Visual C++ 2015-2022 for the SC Live 2, SC Live 4, Prime GO and Prime GO+. Windows only. A unit playing standalone needs no driver at all.

Check the source switch for that channel on the front panel. Denon DJ's documented cause is the switch on Line instead of Engine: on Line the display reads Line In and all deck control and lights are disabled by design. Flip it to Engine and the deck comes back at once. If the deck is alive and the track still will not load, the drive rule applies: every kind of storage on the Prime 4, including the internal SATA bay, must be FAT32 or exFAT with an MBR partition structure.

Denon DJ publish three routes, wireless recommended, an installer application, or a USB drive formatted exFAT or FAT32 with the .img file in its root, and three warnings that matter more than the routes: unplug every peripheral such as Control One, Micro DMX or LC6000 before updating, do not power off during a USB update, and remove any drive carrying the update file before rebooting into firmware update mode. Denon DJ publish no recovery procedure for power lost mid-update, so the answer is mains power, a table, and never the day of a gig.

That the drive has stopped remembering, not playing. AlphaTheta's cause for USB FULL on the CDJ-3000 and CDJ-3000X is one sentence: recording and the saving of cue points are disabled for lack of free space on the drive. Playback continues. A recording in progress stops automatically and is saved up to the moment before the space ran out. The same drive will fail its next rekordbox export, because the library needs 600 kB plus about 103 kB per track of free space. Leave a gigabyte free and both faults disappear.

No. The touch display ignoring you or hitting the wrong spot has one documented answer, TOUCH DISPLAY CALIBRATION in the UTILITY menu. A Hot Cue or the reverse lever firing late is Quantize waiting for the nearest beat, so turn Quantize off. A deck that will not load another track while one is playing is LOAD LOCK set to LOCK. Freezes and blackouts were fixed by named firmware releases, and AlphaTheta's own note on 3.22 says loading Device Library format still works and you should feel free to update. A factory reset of a player that is not yours removes the resident's settings and answers none of these. Try the settings first, then the firmware, and leave the reset alone.

Because of a firmware fault AlphaTheta log in their own change histories: AIFF at 24-bit/48kHz stopped playing and could not be loaded to a deck. They fixed it on the CDJ-2000NXS at firmware 1.25, on the CDJ-900NXS at 1.30 and on the XDJ-700 at 1.10, and a narrower entry, certain AIFF files did not play properly, on the XDJ-RR at 1.03 and the XDJ-RX2 at 1.38. A player below those versions refuses the file and nothing on the drive is wrong. Update the firmware before the gig, or export a 16-bit/44.1kHz version of the track as the fallback.

Two things, both published. Space: on a CDJ, when the drive fills, the recording stops automatically and the file is saved up to the moment before the space ran out. Serato splits files at 3 hours at 16-bit or 1 hour 50 minutes at 24-bit, and records 24-bit by default. Rights: rekordbox state the recording function cannot be used with streaming tracks, due to copyright restrictions set by the streaming services. Where the file lands also differs by unit. The OMNIS-DUO records WAV to USB only, never to the SD card, and not when Bluetooth is the source. The Mixstream Pro+ writes to a folder called Sessions on the connected media, and Serato to a Recording folder inside _Serato_.

Yes. 3.30 was released on 21 October 2025 and withdrawn after AlphaTheta's notice of 4 November 2025 reported playlists not being displayed after the update; the instruction at the time was a temporary downgrade to 3.20. Their follow-up of 7 January 2026 explains it as the Device Library to OneLibrary transition, states that no music or data was deleted, and says the CDJ-3000 has reverted to Device Library. The safe version today is the one the firmware matrix names, and AlphaTheta's own note on the release after the withdrawal says feel free to update. At the gig: do not update or downgrade a venue's player. If your playlists do not display, the tracks are still on the drive; browse by folder and tell the venue the version number after the set.

If it worked last week and does not today, it is almost never the format, because a file system does not change on its own. Check it anyway because it costs nothing: exFAT or FAT32, never NTFS. Then go to the real cause, which Denon name themselves: a drive pulled instead of ejected. The damage lands on the Engine library, not the music. Engine DJ publish the recovery: close Engine DJ, delete the Database2 folder inside Engine Library at the root of the drive, restart and resync from Sync Manager. That deletes the index, not your audio.

The ground wire, before it is ever the deck. Connect it to the SIGNAL GND terminal on the mixer and make sure it is tight, because both AlphaTheta and Technics state that a ground that is missing OR LOOSE produces mains hum. If the earth is right, it is what the connection cable is lying next to: a mains lead or a lighting circuit running alongside a phono cable gets picked up and amplified with the music, which is why a hum can appear when the venue turns the house lights on. On a deck with a removable headshell, dirty headshell terminals raise hum too, and that one comes and goes rather than sitting steady.

Physical checks before any driver, and they cost about ninety seconds. Use the cable that came with it, because a charge-only cable powers the unit and carries no data, so it lights up and the computer never sees it. Then take out any USB hub and connect direct, unplug the other USB devices, try a different port, and close background applications before opening the DJ software. On Windows a controller usually needs the maker's own audio driver; on macOS most are class compliant and need none.

exFAT or FAT32, and Denon mark exFAT as the recommended one. Use FAT32 anyway if you ever play a booth you do not own. Nine of the AlphaTheta players documented on this site refuse exFAT outright, every CDJ-2000 among them, and those are still the decks in most clubs. FAT32 is the only file system that mounts on both sides of the booth. It is also all that crosses: an Engine library is not a rekordbox library.

They are the two formats rekordbox uses to write the index onto your drive, the one a player reads to show playlists, cues, grids and artwork with no computer attached. A player reads one or the other. The trap is that it does not follow the age of the gear: the CDJ-3000 is Device Library and the CDJ-3000X is OneLibrary, often in the same booth. Keep rekordbox at 7.2.13 or later and convert each drive once, and every export then writes both formats onto the same stick.

The database landed corrupt, classic after pulling the drive without ejecting. First, in rekordbox, open Preferences, DJ System, Device and check that Delete Tracks is OFF. With it on, deleting a playlist from the device also deletes the audio of every track no other playlist on that drive uses. Then delete the playlists from the device, re-sync them fresh, and eject with the rekordbox eject button. If the device errors, copy your music off, format clean, export again.

Work in order. Check there is free space on the drive. Then open Preferences, DJ System, Device and check that Delete Tracks is OFF, because with it on, deleting a playlist from the device also deletes the audio of every track no other playlist on that drive uses. Now delete the device playlists, re-sync fresh, and eject with the rekordbox eject button. If the export keeps failing, the drive itself is usually the problem, copy the music off and reformat FAT32/MBR before exporting again.

If the operating system sees the drive but rekordbox does not, it is almost always the file system or the partition map, not the software. Confirm the drive is FAT32 with an MBR scheme, then restart rekordbox with the drive already connected.

The audio is on the drive but the analysis data is missing or unreadable. Usually the tracks were copied manually instead of exported from rekordbox, or the export was interrupted. Re-analyse in rekordbox and export properly and the waveforms come back.

Official behaviour: the player automatically plays a Beat Loop if it cannot start the next track when the end of the current one is reached, so the room never goes silent. If nothing was loaded, that is normal. If it fires when your next track was ready, the player could not read it: treat the drive as suspect and mix out on the other player.

Two, identical, with the same export on both. A second drive is the only backup that works when you are already standing in the booth, and it turns a dead gig into a ten-second swap.

32-64 GB is the sweet spot. Big enough for a full working library, small enough that FAT32 formats without a fight. Bigger drives are slower to format, slower to scan and no more useful for a single gig.

Use rekordbox's own Backup Library with "include music files" checked, then restore that backup on the new machine. Copying only the audio files loses every cue, grid and playlist, which is the mistake almost everyone makes once.

Often, yes, and what decides it is what you do next. Stop writing to the drive: every new write can overwrite the music you are trying to save. If a computer still detects it at all, even showing zero files or offering to format it (say no), recovery software has a real chance, and the two we point at both scan free so you see what is recoverable before paying. A drive that is detected nowhere, with no light or physical damage, is a hardware job for a recovery lab.

The rescue kit does, by design. On your first visit the site saves the emergency start page, every screen of all five rescue routes (USB not recognized, music will not load, no sound, frozen player, and a failed rekordbox export), the checklist, the pocket card, the rekordbox reference, the dictionary and search onto your device, and from then on those load with no signal at all. Conditions: you must have opened the site once while online, and clearing your browser data clears the kit until the next online visit. Adding it to your home screen protects the stored kit best, especially on iPhone.

A quality metal-bodied 32-64 GB stick from a major brand, and buy two identical ones, always. Our gear page lists the exact models we trust.