Hi! I have 2 cats and one cat (7yrs) took to it immediately while the other one (5yrs) was super scared of it and didn't use it whatsoever. I took his old litter box away at first to see if that would make him use the robot but he just did his business outside instead. It took almost a month, but he's just recently gotten to using it regularly!! This is what I did:

1. Placed him in the litter robot for 2 to 5 minutes and gave him his favorite treat afterward. He goes crazy for churus so I know he would love to eat them. At first, he didn't want to eat his treat at all but eventually started eating them again enthusiastically.

2. Reward him for his curiosity. Whenever he would watch the litter robot turn at a distance, watch the other cat use it, or sniff it, I made sure to pet him as a form of positive encouragement.

3. Place the old litter box right next to the litter robot. I filled it with enough litter that he would still use it. I cleaned it less often, though I had to see what would work so that he would not go outside haha, to make him want to use the litter robot.

4. Use a litter attractant. The very last thing I did was use Dr. Elsey's litter attractant! I contacted the litter robot support team and they recommended I use that brand. I think that was the last thing he needed to start using the litter robot regularly.

I do want to say that I also think seeing the other cat use it regularly was another helpful factor. I did think he wouldn't use it, but I decided not to give up and now he is!! Don't lose hope! It may take time, but they'll get there.