SERATO DOES NOT SEE
THE CONTROLLER

When Serato shows the hardware as disconnected, Serato's own list is four items: "Ensure you have the hardware drivers installed from the hardware manufacturers website or installation CD.", "Connect the Serato DJ hardware directly to a USB port on your computer, not via a USB hub.", "Try all USB ports, some work better than others.", and "Disconnect other USB devices."

The hub line is the one that catches touring DJs. A laptop with two ports and a hub for everything else is the normal setup, and it is the setup Serato tell you to undo first. Plug the controller straight into the computer and move the hub to the other port. If that fixes it, the hub was the fault, whatever it cost.

Serato then list the things that make a connection unstable rather than absent: check for software updates in the setup screen or at serato.com, close other running applications, disable wireless networking and Bluetooth, and run the laptop connected to a power supply.

A connection that comes and goes is almost always a power or bandwidth question, not a driver one. Mains power, wireless off, nothing else on the bus. Then see whether it holds.

inMusic, who make Serato hardware under the Denon DJ, Rane and Numark names, publish one troubleshooting article for all of them. For a unit the software does not see: "Restart Your Computer", "Install/Reinstall Drivers" from the maker's own site, "Try Another USB Port Or Cable", make sure the unit is in Computer Mode where it has one, and on macOS reconfigure MIDI Studio so the device is recognised.

Computer Mode and MIDI Studio are the two nobody thinks of. A standalone unit that boots into its own operating system is invisible to Serato until it is switched to the mode that hands control to the laptop. And a Mac that once saw the device under a different name can keep a stale entry in MIDI Studio that blocks the new one.

Their power notes are the ones a DJ forgets: test in a different location because a venue may need a power conditioner, plug directly into a wall outlet rather than a power strip, replace the USB cable if the controller is bus powered, and use a direct USB-B to USB-C cable rather than an adapter.

Take the adapter line seriously. A USB-C laptop with a USB-B controller through a small adapter is the commonest setup in the world and the least reliable link in it. One cable with the right plug on each end removes a failure point that no setting can fix.

On audio, the same article says to raise the audio buffer starting around 5 to 10, restart the computer before a performance, connect the power adapter because a low battery throttles the processor, close background applications, check that the operating system's own sound input and output are not set to the controller, and disable "Use Laptop Speakers" in Serato when external speakers are in use.

Two of those are settings that look right and are not: the operating system's own sound device set to the controller, which steals the audio from Serato, and Use Laptop Speakers left on from a rehearsal. The full no-sound order is on its own page, and on Windows there is one cause nobody would guess.

If the tracks play backwards on a DVS setup, Serato's cause is simple: "The inputs (from the turntables or CD players) are the wrong way around." Their fix is to "Try swapping the red and white RCA cables around", and they warn that it can look right and still be wrong: "Even if it looks right ie, the red RCA cable is in the red input, and the white RCA is in the white", the turntable or headshell may be wired the other way internally.

Swap the pair and play a track. If it runs the right way, leave the cables swapped and label them, because the fault is inside the deck and it will still be there next week.

At the decks, the fast items are the port, the hub, the cable, Computer Mode and a restart. Drivers and MIDI Studio are not booth jobs.

If it still will not connect, take the laptop out of the set. Any drive you have already exported plays in the club's players with no computer involved. Fix the connection tomorrow, on a table, with the maker's page open.