Troubleshooting
Start with DMX Doctor. It checks the whole chain, from your fixture setup to what is reaching your lights.
Start with DMX Doctor
Most lighting problems come down to a short list of causes: a fixture patched to the wrong address, a live override still holding a channel down, a cable, or an interface that has quietly dropped out. DMXDesktop can now find nearly all of them for you. DMX Doctor sits in the main header, where the old Health tab used to be, and checks the whole chain from your fixture setup through to what is actually reaching your lights.
The most common reason a fixture will not respond is a Live Control that is active but has not been cleared. Dragging a fader to zero forces that channel to stay at zero, which overrides any effect trying to run. Clear the Live Control rather than dragging it down. DMX Doctor now spots this for you and names the override that is responsible.
Work through the three steps below in that order. Get help is the last one, not the first, and by the time you reach it the app has usually worked the answer out already.
Three steps, in order
Diagnose it, check what already went wrong, then ask us. Most problems stop at step one.
Run DMX Doctor
DMX Doctor is in the main header. It checks your fixtures for mis-typed colour channels, broken lamp grouping, addressing problems and laser-specific issues, each explained in plain language. Then it checks what is happening right now: whether output is reaching the lights at all, whether the master dimmer is at zero, and whether a live override or Dark On Silence is why a fixture looks wrong. Most findings have a one-click fix, you can apply one across many fixtures at once, and anything applied can be undone. A channel table shows what is genuinely going out on the wire, not what should be.
Check Recent problems
A live check only sees the present moment, so the interface that dropped out an hour ago, the show that failed to load or an engine that restarted were all invisible. The Recent problems panel reads the logs for you and reports what happened, when it was last seen and how often, in plain language. Clearing an entry dismisses it rather than deleting anything, so if you do end up contacting us the logs still arrive intact.
Get help
Get help raises a support ticket with your diagnostics already attached, so you do not have to describe the problem twice. It is deliberately the last step: where the guided checks used to run out of ideas and offer a ticket, they now consult your recent problems first and can usually give you an answer instead.
If a group is behaving oddly and nothing obvious explains it, open the Output window's Sources view. It shows everything acting on the rig at once and names whatever is blocking anything. See DMX Priorities.
Things you no longer have to troubleshoot
Several long-standing failure modes are handled by the app itself in v1.0.52.
The app starts even if Windows MIDI is stuck
A stuck Windows MIDI service could hold DMXDesktop before it ever got as far as opening a window, so the app appeared to do nothing at all, with no window and no error message to go on. It now gives up waiting and starts normally, and the MIDI settings page explains what happened and how to clear it.
You are warned before your computer runs short
If memory, disk space or open files run low you are told plainly, rather than left with an app behaving oddly for no visible reason. Your show is not stopped.
The database repairs itself at startup
If the database cannot be read when the app starts, DMXDesktop now repairs it and carries on instead of refusing to open. Backups and restores are more reliable too.
DMX output recovers on its own
If the lighting engine failed to start, output used to stay stopped until you restarted the app. It now recovers by itself.
Tips & Best Practices to Prevent Issues
- ✓ Always plan your patch/layout and channel usage before a show; avoid overlaps.
- ✓ Use high-quality, properly rated DMX cables (120 Ω twisted pair).
- ✓ Always use a DMX terminator at the last fixture in the run.
- ✓ Keep DMX chains under 32 fixtures or use a splitter/regenerator.
- ✓ Label and map your cables, universes, and fixture addresses.
- ✓ Do a "fixture identification" pass (turning on one light at a time) to ensure each fixture is correctly patched and addressed.
- ✓ Keep firmware/software up-to-date, but test major updates in a safe environment first.
- ✓ Use backup setups (e.g. redundant paths or fallback universes) when possible.
- ✓ In DMXDesktop, when patching new fixtures, rely on the built-in "next available address" prompter, but always double-check.
- ✓ When troubleshooting, isolate one fixture or group at a time - don't try to fix the whole system at once.
Still Need Help?
Run DMX Doctor first. If it cannot solve it, Get help inside the app raises a ticket with your diagnostics already attached.
