nats-io/nats-server · error

could not send control=%d: %v

Error message

could not send control=%d: %v

What it means

Windows ProcessSignal: sending the selected service control command via s.Control(cmd) returned an error — the service exists but rejected the control (e.g. service already stopping, permission issue, or SCM communication failure). The control code and error are echoed; the signal was not delivered.

Source

Thrown at server/signal_windows.go:94

	case CommandStop, CommandQuit:
		cmd = svc.Stop
		to = svc.Stopped
	case CommandReopen:
		cmd = reopenLogCmd
		to = svc.Running
	case CommandReload:
		cmd = svc.ParamChange
		to = svc.Running
	case commandLDMode:
		cmd = ldmCmd
		to = svc.Running
	default:
		return fmt.Errorf("unknown signal %q", command)
	}

	status, err := s.Control(cmd)
	if err != nil {
		return fmt.Errorf("could not send control=%d: %v", cmd, err)
	}

	timeout := time.Now().Add(10 * time.Second)
	for status.State != to {
		if timeout.Before(time.Now()) {
			return fmt.Errorf("timeout waiting for service to go to state=%d", to)
		}
		time.Sleep(300 * time.Millisecond)
		status, err = s.Query()
		if err != nil {
			return fmt.Errorf("could not retrieve service status: %v", err)
		}
	}

	return nil
}

View on GitHub (pinned to 3a66a489d2)

Solutions

1. Check service state with sc query before sending the control
2. Run from an elevated shell to rule out access-denied
3. Retry after the service reaches a stable state

When it happens

Trigger: Thrown at server/signal_windows.go:94 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of nats-io/nats-server@3a66a489d2 (2026-09-02). Data as JSON: /api/errors/7d84babb37d3e45c. Report an issue: GitHub.