hashicorp/nomad · error

unable to stop existing service - %w

Error message

unable to stop existing service - %w

What it means

Wraps the failure of stopping an already-running Nomad Windows service during `windows install`. The command detected a running service and called Windows service manager Stop; the underlying SCM error is preserved via %w. Install aborts so the stale binary/service state is not half-replaced.

Source

Thrown at command/windows_service_install.go:158

		nmdSvc, err := m.GetService(winsvc.WINDOWS_SERVICE_NAME)
		if err != nil {
			return fmt.Errorf("could not get existing service to stop - %w", err)
		}

		// If the service is running and the reinstall
		// option was not set, return an error
		running, err := nmdSvc.IsRunning()
		if err != nil {
			return fmt.Errorf("unable to determine service state - %w", err)
		}
		if running && !opts.reinstall {
			return fmt.Errorf("service is already running. Please run the\ncommand again with -reinstall to stop the service and install.")
		}

		if running {
			c.Ui.Output("  Stopping existing nomad service")
			if err := nmdSvc.Stop(); err != nil {
				return fmt.Errorf("unable to stop existing service - %w", err)
			}
		}
	}

	// Install the nomad binary into the system
	if err = c.binaryInstall(opts); err != nil {
		return fmt.Errorf("binary install failed - %w", err)
	}

	c.Ui.Output(fmt.Sprintf("  Nomad binary installed to: %s", opts.binaryPath))

	// Create a configuration directory and add
	// a basic configuration file if no configuration
	// currently exists
	if err = c.configInstall(opts); err != nil {
		return fmt.Errorf("configuration install failed - %w", err)
	}

View on GitHub (pinned to 482b49bf1a)

Solutions

1. Re-run the command with -reinstall so the flow stops the service itself before installing
2. Open an elevated (Administrator) PowerShell/cmd and retry the install
3. Run `sc query nomad` / `sc.exe stop nomad` manually, wait for STOPPED state, then install again
4. Reboot to clear a service stuck in marked-for-deletion or stop-pending state

Example fix

// before
nomad windows install
// after
nomad windows install -reinstall

sc := exec.Command("sc.exe", "query", "nomad"); out, err := sc.Output()
if err == nil && strings.Contains(string(out), "RUNNING") {
	fmt.Println("Service running — use -reinstall or stop it first:",
		exec.Command("sc.exe", "stop", "nomad").Run())
}

if err := nmdSvc.Stop(); err != nil {
	var exitErr *exec.ExitError
	if errors.As(err, &exitErr) && isAccessDenied(exitErr) {
		// prompt for elevation and retry
	}
	return fmt.Errorf("unable to stop existing service - %w", err)
}

When it happens

Trigger: Running `nomad windows install` while the Nomad service is running and the golang.org/x/sys windows svc manager Stop call fails (access denied, service marked for deletion, SCM timeout).

Common situations: Installing over a service started under a different elevation; prior uninstall left the service in marked-for-deletion state; service hung and did not respond to the stop control within the timeout.

Related errors

• service install failed - %w
• binary install failed - %w
• service registration check failed - %w
• unable to get existing service - %w
• unable to configure service - %w

AI-assisted analysis of hashicorp/nomad@482b49bf1a (2026-09-04). Data as JSON: /api/errors/68f641aca8db653f. Report an issue: GitHub.