1. Identify the underlying medical condition. If your cat is urinating on the furniture suddenly, it's important to take them to the vet to rule out any underlying medical conditions that could be causing the problem.
2. Clean up the affected areas. Once you know that your cat is not suffering from any medical problems, you need to clean up the affected areas thoroughly. Use a pet-safe cleaner that is specifically designed to remove cat urine.
3. Block access to the furniture. If your cat is urinating on a particular piece of furniture, try blocking their access to it. You can do this by placing a baby gate in front of the furniture, or by covering it with a tarp.
4. Provide alternative litter boxes. If your cat is not using their litter box, they may need more or different types of litter boxes. Try placing several litter boxes in different locations around the house, and experiment with different types of litter.
5. Make the litter box more attractive. Cats are attracted to clean, private litter boxes. Make sure your cat's litter box is clean, and place it in a quiet, secluded spot.
6. Encourage your cat to use the litter box. You can encourage your cat to use the litter box by placing treats or toys in the litter box. You can also try pheromone sprays, which can help to attract cats to the litter box.
7. Be patient. It may take time for your cat to stop urinating on the furniture. Be patient, and consistent with your training, and you should eventually see results.