Lawn mower encountered an error

The Lawn mower encountered an error trigger fires when a mower reports a problem while it is working. Use it to notify you quickly, pause related automations, or turn on a nearby light before you go outside to check what happened.

Using this trigger from the user interface

If you prefer building automations visually, Home Assistant walks you through this trigger step by step. You pick what to watch, tweak a few options, and save. No YAML knowledge required.

To use this trigger in an automation:

1. Go to Settings > Automations & scenes.
2. Open an existing automation, or select Create automation > Create new automation.
3. In the When section, select Add trigger.
4. From the search box, search for and select Lawn mower encountered an error.
5. Select what you want to monitor. Under By target (see Targets), pick the area where your mower is used. You can also select a floor, a device, a specific entity, or a label.
6. Under Trigger when (see Behavior), pick Each, First, or All.
7. Under For at least, set how long the mower must stay in the error state before the trigger fires. Leave it at zero to fire immediately.
8. Select Save.

Options in the UI

Using this trigger in YAML

If you work directly in YAML, or you want to know exactly what Home Assistant does under the hood, this section has the technical reference. It lists the field names you use in YAML, their types, and which ones are required.

In YAML, refer to this trigger as lawn_mower.errored. A basic example looks like this:

trigger: lawn_mower.errored
target:
  entity_id: lawn_mower.backyard

This fires when lawn_mower.backyard enters the error state.

Options in YAML

YAML sometimes provides additional options for more complex use cases that are not available through the UI.

Targets of the trigger

This trigger requires a target. The target is the object that Home Assistant will watch. You can select a single entityAn entity represents a sensor, actor, or function in Home Assistant. Entities are used to monitor physical properties or to control other entities. An entity is usually part of a device or a service. [Learn more], a device, an area, a floor, or a label as a target, and Home Assistant will watch every matching lawn_mower entity behind that target.

• Entity: one specific lawn_mower entity, such as lawn_mower.living_room.
• Device: every lawn_mower entity that belongs to a device.
• Area: every lawn_mower entity in a room or area.
• Floor: every lawn_mower entity on a floor.
• Label: every lawn_mower entity that shares a label.

You can also select different target types in one trigger. For example, you can add a specific entity and an area as targets in the same trigger to monitor both of them at once.

Behavior with multiple targets

When you target more than one entity (or select an area, floor, or label that contains several), the Trigger when option controls how the trigger responds:

• Each (any in YAML, default): the trigger fires every time any one of the targeted entities transitions. For example, if you monitor three motion sensors in the living room and someone walks past sensor 1, the automation fires. When they walk past sensor 2 a moment later, it fires again. Every individual event counts.
• First (first in YAML): the trigger fires only on the first transition in the targeted group, then waits until all targeted entities have reset before it fires again. For example, if you monitor the same three motion sensors, the automation fires when the first one picks up movement (someone entered the room). The other two firing afterward are ignored, so you get one notification per “someone walked in” event instead of three.
• All (last in YAML): the trigger fires only after the last targeted entity in the group has fired, meaning all of them are now in the expected state. For example, if you monitor the lights in the living room, bedroom, and hallway, the automation fires only once all three have turned off. This is useful for scenarios like “start the robot vacuum only after every light on the floor is off,” so you know the room is truly empty.

Good to know

• The trigger only fires when a mower changes into the error state from a known state. If a mower comes back from unavailable or unknown, that recovery does not fire this trigger.
• Use For at least if you want to ignore a brief status change while the mower recovers on its own.

Try it yourself

Ready to test this? Go to Settings > Automations & scenes, create a new automation, and add this trigger. Save the automation, then change the state of the targeted entity to watch the trigger fire on your actual entitiesAn entity represents a sensor, actor, or function in Home Assistant. Entities are used to monitor physical properties or to control other entities. An entity is usually part of a device or a service. [Learn more].

More examples

Real scenarios where this trigger fires in automations and scripts. Copy any example and adapt it to your setup.

Automation: Send an urgent alert when the mower needs help

If the mower gets stuck under a bush or reports another fault, send an alert right away so you can fix the problem before the schedule falls behind.

• Trigger: Lawn mower encountered an error
  • Target: Backyard mower
• Action: Send a notification message
  • Target: My Device (notify.my_device)

alias: "Alert when the mower reports an error"
triggers:
  - trigger: lawn_mower.errored
    target:
      entity_id: lawn_mower.backyard
actions:
  - action: notify.send_message
    target:
      entity_id: notify.my_device
    data:
      title: "Lawn mower needs attention"
      message: >
        The backyard mower reported an error.
        Check it in the yard or in the app.

Automation: Turn on the porch light before you go outside

If the mower reports an error after dark, turn on the porch light so you can see the yard before stepping outside.

• Trigger: Lawn mower encountered an error
  • Target: Backyard mower
  • For at least: 00:00:15
• Condition: Sun: after sunset
• Action: Turn on light

alias: "Turn on the porch light when the mower errors"
triggers:
  - trigger: lawn_mower.errored
    target:
      entity_id: lawn_mower.backyard
    options:
      for: "00:00:15"
conditions:
  - condition: sun
    after: sunset
actions:
  - action: light.turn_on
    target:
      entity_id: light.porch

Still stuck?

The Home Assistant community is quick to help: join Discord for real-time chat, post on the community forum with the trigger you’re using and what you expected to happen, or share on our subreddit /r/homeassistant.