Try scooping some poop out of the other box, place it in the new one and unplug the box until he/she uses it. Then plug it in once a day and hit the button to cycle but don't leave it going. Unplug it once it has cycled. I have the same issues with my cats but we are on week 3 or 4 and they are almost never using the old cat box anymore. Slow transition. They need to trust it.