Troubleshooting

Start with the lamps at the right of the status line and the amber held chip. Between them they say what LIGHT thinks is wrong.

Nothing lights up

Work down this list. It stops being LIGHT's problem at step 5.

1. Is LIGHT live? LIGHT always opens offline. Press offline in the top bar. If it opens the Output settings instead, no universe is switched on: turn on Art-Net or sACN for your universes.
2. Is blackout on, or the master down? B toggles blackout. Check the master fader and each layer's master.
3. Is something held? If the held · N chip is showing, open it. A group pulled down, a muted fixture or a bypassed layer each keeps light off the rig, and the row has the button that ends it.
4. What does the output lamp say?
   • sends failing: macOS is blocking LIGHT from the network. See Sends failing.
   • no reply: packets are going out but no node answered. Check the cable, the node's power and its IP address, and the output adapter in Settings ▸ Output.
   • sending ·N: N nodes are answering. Carry on.
5. Does the DMX monitor move? In Settings ▸ Output, pick the universe and fire a look. If the bars move, LIGHT is sending. Check the node's universe matches the Art-Net universe or sACN universe, and that the fixture's address and DMX mode match the patch.
6. Test one channel. In the channel check, hold the fixture's first channel at 255. If the fixture reacts, the line is good and the patch is wrong. If it doesn't, the problem is between the node and the fixture.

Some fixtures stay dark

• The fixture may be muted in the Rig view, or its group pulled down on the groups row. Both show in the held chip.
• N dark in the held chip: those fixtures use a profile LIGHT can't drive. show in Rig lists them. Import a proper GDTF file for them.
• The look doesn't include that fixture's group. Open the look and check its parts.
• Two fixtures share channels. Look for the address conflict warning.

Sends failing

macOS is refusing LIGHT's packets. Almost always it is the Local Network permission. Open System Settings ▸ Privacy & Security ▸ Local Network, turn LIGHT on, then quit and reopen LIGHT. See Local network permission.

The wrong fixture lights, or colours are wrong

• The wrong fixture: find each fixture with its magnifier in the Rig view (hold until the ring fills). If another one lights, its address on the truss doesn't match the patch.
• Wrong colours, or it strobes: the fixture is in a different DMX mode from its profile. Set the mode on the fixture to the one in the Profile column, or patch it with the right mode.
• A moving head moves the wrong way: fix it in Calibration, not in the looks.

Resolume does nothing

1. In LIGHT, Settings ▸ Sync · MIDI: is the Resolume link listening? A new show starts with it off.
2. In Resolume, Preferences ▸ OSC: is OSC Output on, sending to 127.0.0.1 on port 7700 (or whatever LIGHT's port says)?
3. Launch a column in Resolume and watch the box under the Resolume link.
   • Nothing appears: Resolume isn't sending to LIGHT's port.
   • Messages appear marked ignored — other machines are blocked: Resolume is on another computer. Set other machines to accepted.
   • Messages appear but nothing fires: check follow columns is on and the column exists in the song that is playing.
4. The osc lamp is red: another app holds the port. Quit it (often another lighting app, or a second copy of LIGHT), then switch listening off and on.

The whole setup is in Follow Resolume.

The MIDI controller does nothing

• Check the midi lamp is lit and the controller is listed and switched on under inputs in Settings ▸ Sync · MIDI.
• Check the controller has mappings: load a layout, or use MIDI learn.
• An APC used by Resolume at the same time fires both apps. Switch it off in one of them.
• An Akai APC must be in its generic mode (as it is out of the box) for the ready-made layouts to match.

See Map a MIDI controller.

The tablet can't connect

• It must be on the same network as the adapter chosen under network in Settings ▸ Devices. Venue and hotel Wi-Fi often stop devices seeing each other.
• WATCHING on the tablet: it opened the address without the pairing code. Scan the code from Settings ▸ Devices.
• UNPAIRED: someone pressed unpair every device. Scan the new code.
• A message that the engine would not take this connection: the address isn't one LIGHT serves, or eight devices are already connected. Use the link from Settings ▸ Devices.

See Run it from a tablet or phone.

Engine offline or stalled

The red bar ENGINE OFFLINE — reconnecting… means the window has lost the show engine. ENGINE STALLED means it is connected but not answering. Nothing you press reaches the rig until it clears.

• Give it a few seconds: it reconnects by itself.
• If it doesn't, quit LIGHT and open it again. It comes back with the show, offline.
• On a tablet, this usually means the Mac is asleep, LIGHT has quit, or the Wi-Fi dropped.

LIGHT won't start: port in use

If LIGHT says LIGHT cannot use port 9900, another copy of LIGHT is probably already running: check the Dock and quit it. It offers to run on the next free port instead. If you accept, tablets and phones have to scan the pairing code again. Resolume needs no change: OSC stays on port 7700.

After a crash

Open LIGHT again. It restores the show and what was playing, with output offline so nothing jumps. Check the rig, then go live. It asks once whether to send a crash report; nothing is sent unless you say so. Shows are also backed up as .bak1 to .bak5 beside each show file, in ~/Library/Application Support/LIGHT/projects/.

The licence screen won't let me in

• Licensed to another machine: the key's seats are taken by other Macs. manage your licences → opens your account, where you can free one.
• Trial ended: enter a licence key.
• An activation fails: LIGHT needs the internet for that step. Check the connection, then try again.

Still stuck? Send a note from Settings ▸ Feedback, or include the this machine code from Settings ▸ Licence when you write to support.