microsoft/autogen · error · RuntimeError

The team cannot be loaded while it is running.

Error message

The team cannot be loaded while it is running.

What it means

load_state() overwrites every participant's state, which is unsafe while messages are flowing: it initializes if needed, then refuses with RuntimeError if _is_running is True. The flag is set for the whole duration of the load itself and cleared in a finally block.

Source

Thrown at python/packages/autogen-agentchat/src/autogen_agentchat/teams/_group_chat/_base_group_chat.py:809

            # save_state method because we want to support saving state of remote agents.
            agent_states[name] = await self._runtime.agent_save_state(agent_id)
        # Save the state of the group chat manager.
        agent_id = AgentId(type=self._group_chat_manager_topic_type, key=self._team_id)
        agent_states[self._group_chat_manager_name] = await self._runtime.agent_save_state(agent_id)
        return TeamState(agent_states=agent_states).model_dump()

    async def load_state(self, state: Mapping[str, Any]) -> None:
        """Load an external state and overwrite the current state of the group chat team.

        The state is loaded by calling the :meth:`~autogen_core.AgentRuntime.agent_load_state` method
        on each participant and the group chat manager with their internal agent ID.
        See :meth:`~autogen_agentchat.teams.BaseGroupChat.save_state` for the expected format of the state.
        """
        if not self._initialized:
            await self._init(self._runtime)

        if self._is_running:
            raise RuntimeError("The team cannot be loaded while it is running.")
        self._is_running = True

        try:
            team_state = TeamState.model_validate(state)
            # Load the state of all participants.
            for name, agent_type in zip(self._participant_names, self._participant_topic_types, strict=True):
                agent_id = AgentId(type=agent_type, key=self._team_id)
                if name not in team_state.agent_states:
                    raise ValueError(f"Agent state for {name} not found in the saved state.")
                await self._runtime.agent_load_state(agent_id, team_state.agent_states[name])
            # Load the state of the group chat manager.
            agent_id = AgentId(type=self._group_chat_manager_topic_type, key=self._team_id)
            if self._group_chat_manager_name not in team_state.agent_states:
                raise ValueError(f"Agent state for {self._group_chat_manager_name} not found in the saved state.")
            await self._runtime.agent_load_state(agent_id, team_state.agent_states[self._group_chat_manager_name])

        except ValidationError as e:
            raise ValueError(

View on GitHub (pinned to 027ecf0a37)

Solutions

1. Complete or stop the active run first (exhaust the stream or await stream.aclose()).
2. Use one asyncio.Lock to make run/load_state/reset mutually exclusive per team.
3. For per-request workloads, instantiate a fresh team and load state into it instead of mutating a running one.

Example fix

# before
asyncio.gather(team.run(task="a"), team.load_state(saved))  # one of them raises

# after
lock = asyncio.Lock()
async with lock:
    await team.run(task="a")
async with lock:
    await team.load_state(saved)

async with team_lock:
    await team.load_state(state)  # same lock used for run/reset

try:
    await team.load_state(state)
except RuntimeError as e:
    if "cannot be loaded while it is running" in str(e):
        await active_stream.aclose()
        await team.load_state(state)
    else:
        raise

When it happens

Trigger: Calling await team.load_state(state) while a run_stream generator is active (started but not exhausted/closed), or from a concurrent coroutine during await team.run().

Common situations: Hot-swapping conversation state from a UI 'switch session' action while a run is streaming; concurrent tasks sharing one team instance for run and checkpoint restore.

Related errors

• The team is already running, it cannot run again until it is
• The group chat is currently running. It must be stopped befo
• The group chat has not been initialized. It must be run befo
• The group chat has not been initialized. It must be run befo
• Agent state for {name} not found in the saved state.

AI-assisted analysis of microsoft/autogen@027ecf0a37 (2026-08-15). Data as JSON: /api/errors/4c777ff182efc525. Report an issue: GitHub.