Place the beef, carrot, onion, potatoes, and Guinness into your slow cooker pot.
Blend the Slow Comfortable Stew Sauce Mix with the water and add to the slow cooker, stir thoroughly.
Cover and cook for 4 hours on HIGH or 8 hours on MEDIUM or until the meat is tender and cooked through (keep covered during cooking, cooking times may vary between slow cooker models).
Remove to lid and stand for 5 minutes before serving.