invoke-ai/InvokeAI · error · HTTPException

Unexpected error while resuming queue: {e}

Error message

Unexpected error while resuming queue: {e}

What it means

Thrown by the resume endpoint (PUT /{queue_id}/processor/resume, admin only): any exception from SessionProcessor.resume() is wrapped as a 500 with the exception message embedded. It means the queue processor could not be transitioned back to running for an unanticipated reason (the endpoint doesn't model processor-state conflicts as 4xx).

Source

Thrown at invokeai/app/api/routers/session_queue.py:275

        return [sanitize_queue_item_for_user(item, current_user.user_id, current_user.is_admin) for item in summaries]
    except Exception:
        raise HTTPException(status_code=500, detail="Failed to get queue item summaries")


@session_queue_router.put(
    "/{queue_id}/processor/resume",
    operation_id="resume",
    responses={200: {"model": SessionProcessorStatus}},
)
def resume(
    current_user: AdminUserOrDefault,
    queue_id: str = Path(description="The queue id to perform this operation on"),
) -> SessionProcessorStatus:
    """Resumes session processor. Admin only."""
    try:
        return ApiDependencies.invoker.services.session_processor.resume()
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"Unexpected error while resuming queue: {e}")


@session_queue_router.put(
    "/{queue_id}/processor/pause",
    operation_id="pause",
    responses={200: {"model": SessionProcessorStatus}},
)
def pause(
    current_user: AdminUserOrDefault,
    queue_id: str = Path(description="The queue id to perform this operation on"),
) -> SessionProcessorStatus:
    """Pauses session processor. Admin only."""
    try:
        return ApiDependencies.invoker.services.session_processor.pause()
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"Unexpected error while pausing queue: {e}")

View on GitHub (pinned to 0b6a024f2f)

Solutions

1. Read detail - it contains the underlying exception message
2. Check GET /{queue_id}/processor/status; if already running, resume is unnecessary - skip it
3. Retry after the app finishes startup (processor initialized)
4. Serialize admin processor operations to avoid concurrent resume/pause races

Example fix

// before: blind resume
await fetch(`/api/v1/queue/default/processor/resume`, {method: 'PUT'});
// after: check state first
const s = await (await fetch('/api/v1/queue/default/processor/status')).json();
if (!s.is_started || s.status === 'paused') await fetch('/api/v1/queue/default/processor/resume', {method: 'PUT'});

const s = await (await fetch('/api/v1/queue/default/processor/status')).json();
if (s.is_started && s.status !== 'paused') console.log('processor already running; resume unnecessary');

function isProcessorRunning(s) { return s !== null && typeof s === 'object' && s.is_started === true && s.status === 'idle' || s.status === 'processing'; }

try {
  const res = await fetch('/api/v1/queue/default/processor/resume', {method:'PUT'});
  if (res.status === 500) console.error('resume failed:', (await res.json()).detail);
} catch (e) { console.error('network error during resume:', e); }

When it happens

Trigger: Resuming when the session processor service is in an unexpected state, is not started, or an internal error occurs in the processor's resume path.

Common situations: Calling resume concurrently from multiple admin sessions; invoking before the queue processor thread/service has fully initialized after startup; stale UI holding an old processor state.

Related errors

• Unexpected error while pausing queue: {e}
• Unexpected error while enqueuing batch: {e}
• Unexpected error while listing all queue items: {e}
• Unexpected error while listing all queue item ids: {e}
• Failed to get queue items

AI-assisted analysis of invoke-ai/InvokeAI@0b6a024f2f (2026-08-29). Data as JSON: /api/errors/774ff9abaad55b01. Report an issue: GitHub.