bevyengine/bevy · error · RegisteredSystemError

System {0:?} does not have a RegisteredSystem component. Thi

Error message

System {0:?} does not have a RegisteredSystem component. This only happens if app code removed the component.

What it means

RegisteredSystemError::MissingRegisteredSystemComponent: the SystemId points at an entity that lacks the RegisteredSystem marker component, which only happens if user/app code removed the component from that entity manually.

Source

Thrown at crates/bevy_ecs/src/system/system_registry.rs:853

        self.run_system_with(id, input)
    }
}

/// An operation with stored systems failed.
#[derive(Error)]
pub enum RegisteredSystemError<I: SystemInput = (), O = ()> {
    /// A system was run by id, but no system with that id was found.
    ///
    /// Did you forget to register it?
    #[error("System {0:?} was not registered")]
    SystemIdNotRegistered(SystemId<I, O>),
    /// A cached system was removed by value, but no system with its type was found.
    ///
    /// Did you forget to register it?
    #[error("Cached system was not found")]
    SystemNotCached,
    /// The `RegisteredSystem` component is missing.
    #[error("System {0:?} does not have a RegisteredSystem component. This only happens if app code removed the component.")]
    MissingRegisteredSystemComponent(SystemId<I, O>),
    /// A system tried to remove itself.
    #[error("System {0:?} tried to remove itself")]
    SelfRemove(SystemId<I, O>),
    /// System could not be run due to parameters that failed validation.
    /// This is not considered an error.
    #[error("System did not run due to failed parameter validation: {0}")]
    Skipped(SystemParamValidationError),
    /// System returned an error or failed required parameter validation.
    #[error("System returned error: {0}")]
    Failed(BevyError),
    /// [`SystemId`] had different input and/or output types than [`SystemIdMarker`]
    #[error("Could not get system from `{}`, entity was `SystemId<{}, {}>`", DebugName::type_name::<SystemId<I, O>>(), .1.input_type_id.name, .1.output_type_id.name)]
    IncorrectType(SystemId<I, O>, SystemIdMarker),
    /// System is not present in the `RegisteredSystem` component.
    // TODO: We should consider using catch_unwind to protect against the panic case.
    #[error("The system is not present in the RegisteredSystem component. This can happen if the system was called recursively or if the system panicked on the last run.")]
    SystemMissing(SystemId<I, O>),

View on GitHub (pinned to 396ca72708)

Solutions

1. Avoid despawning or stripping the RegisteredSystem component from system entities
2. Re-register the system to obtain a fresh, valid SystemId
3. If you intentionally removed the component, discard the stale SystemId

When it happens

Trigger: Thrown at crates/bevy_ecs/src/system/system_registry.rs:853 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of bevyengine/bevy@396ca72708 (2026-08-20). Data as JSON: /api/errors/033c06e784ccd919. Report an issue: GitHub.