A Home Assistant automation can look correct and still fail to run. The quickest way to find the cause is to test the three separate stages: trigger, conditions, and actions. Avoid deleting and recreating the automation until you know which stage is failing.
1. Confirm the automation is enabled
Open Settings → Automations & scenes and select the automation. Check that its enable switch is on. If it was recently edited, save it and confirm the displayed configuration reflects the latest changes. Also check whether Home Assistant was restarted or restored from a backup around the time the problem began.
2. Open Traces before changing anything
Open the automation and choose Traces. Select the latest run, if one exists. A trace shows which steps executed and where processing stopped. If there is no new trace when you expect the automation to fire, investigate the trigger first. If a trace exists but the sequence stops, inspect the conditions and action steps shown in that run.
3. Test the trigger independently
Check the exact entity ID and the event that should start the automation. A state trigger for a light turning on is not the same as a trigger for its brightness changing. Likewise, a numeric-state trigger fires when a value crosses the configured threshold; it does not necessarily fire simply because the entity is already above that value when the automation is loaded.
- Open the triggering entity and confirm its current state and recent history.
- Check that the entity ID has not changed after renaming or replacing a device.
- For event, webhook, or device triggers, confirm the relevant event or device action is actually being received.
- For time triggers, verify the configured time and Home Assistant’s time zone.
4. Check every condition
One false condition can prevent all actions from running even when the trigger worked. Look for conditions involving time windows, presence, numeric thresholds, device states, or templates. Compare the values in the trace with the values you expected at that moment. Pay particular attention to exact entity IDs and capitalization in templates.
If several conditions are grouped together, remember that an ordinary condition sequence generally requires every condition in that sequence to pass. Test a suspected condition separately rather than removing all safeguards at once.
5. Run the actions manually—carefully
Use the automation’s action-run control only when it is safe to execute those actions immediately. Manual execution helps distinguish an action problem from a trigger problem, but it may not reproduce the original trigger variables or event data. A notification action might work manually while a template that depends on trigger data still fails during a real run.
Check the target entity, service/action name, required fields, and any template output. For physical devices, avoid manually testing actions that could unlock doors, open gates, disable alarms, or operate appliances unsafely.
6. Check logs and integrations
If the trace points to an action failure, open Settings → System → Logs and look for errors at the same time. A temporarily unavailable integration, authentication problem, or device that no longer responds can make an action fail even when the automation logic is valid.
7. Make one change, then retest
Change only the setting identified by the evidence. Save the automation, reproduce the original trigger, and check the next trace. Changing several triggers and conditions together makes it harder to identify the real cause.
Quick diagnosis
- No trace: check enable state, trigger configuration, entity ID, and whether the event occurred.
- Trace stops at a condition: inspect the condition’s actual inputs and expected values.
- Action reports an error: inspect logs, target entity availability, and action data.
- Manual run works but real trigger fails: compare trigger type, trigger variables, and conditions at the real event time.
The key is to use the trace as evidence. In most cases, identifying the first stage that fails is faster and safer than rebuilding the entire automation.
Official source: Home Assistant: Troubleshooting automations explains how traces help identify trigger, condition, and action failures.
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Review note: Checked against official documentation on October 19, 2026. This is a documentation-based guide, not a report of hands-on testing on a specific Home Assistant installation.
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Image credit: Unsplash, dada design.