{"record":{"id":"881c2b8f451f6d6b","repo":"bevyengine/bevy","slug":"system-0-was-not-registered","errorCode":null,"errorMessage":"System {0:?} was not registered","messagePattern":"System (.+?) was not registered","errorType":"exception","errorClass":"RegisteredSystemError","httpStatus":null,"severity":"error","filePath":"crates/bevy_ecs/src/system/system_registry.rs","lineNumber":845,"sourceCode":"        input: I::Inner<'_>,\n    ) -> Result<O, RegisteredSystemError<I, O>>\n    where\n        I: SystemInput + 'static,\n        O: 'static,\n        S: IntoSystem<I, O, M> + 'static,\n    {\n        let id = self.register_system_cached(system);\n        self.run_system_with(id, input)\n    }\n}\n\n/// An operation with stored systems failed.\n#[derive(Error)]\npub enum RegisteredSystemError<I: SystemInput = (), O = ()> {\n    /// A system was run by id, but no system with that id was found.\n    ///\n    /// Did you forget to register it?\n    #[error(\"System {0:?} was not registered\")]\n    SystemIdNotRegistered(SystemId<I, O>),\n    /// A cached system was removed by value, but no system with its type was found.\n    ///\n    /// Did you forget to register it?\n    #[error(\"Cached system was not found\")]\n    SystemNotCached,\n    /// The `RegisteredSystem` component is missing.\n    #[error(\"System {0:?} does not have a RegisteredSystem component. This only happens if app code removed the component.\")]\n    MissingRegisteredSystemComponent(SystemId<I, O>),\n    /// A system tried to remove itself.\n    #[error(\"System {0:?} tried to remove itself\")]\n    SelfRemove(SystemId<I, O>),\n    /// System could not be run due to parameters that failed validation.\n    /// This is not considered an error.\n    #[error(\"System did not run due to failed parameter validation: {0}\")]\n    Skipped(SystemParamValidationError),\n    /// System returned an error or failed required parameter validation.\n    #[error(\"System returned error: {0}\")]","sourceCodeStart":827,"sourceCodeEnd":863,"githubUrl":"https://github.com/bevyengine/bevy/blob/396ca727080776bd313bb892423b7d94e03b81b4/crates/bevy_ecs/src/system/system_registry.rs#L827-L863","documentation":"RegisteredSystemError::SystemIdNotRegistered: a system was run (or otherwise operated on) by SystemId, but no system with that id exists in the world's system registry — usually because it was never registered or was removed.","triggerScenarios":"Thrown at crates/bevy_ecs/src/system/system_registry.rs:845 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":["Register the system first via world.register_system(...) or app.register_system(...) and store the returned SystemId","If the system was removed with remove_system, do not reuse its old SystemId","Use register_system_cached / run_system_cached to get automatic registration by type"],"exampleFix":null,"handlingStrategy":"try-catch","validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"396ca727080776bd313bb892423b7d94e03b81b4","analyzedAt":"2026-08-20T16:12:39.808Z","contentChangedAt":"2026-08-20T16:12:39.808Z","schemaVersion":2},"datasetVersion":"2026-09-14T00:17:10.932Z"}