My guess is he hates the Litter Robot (LR). I used that thing for nearly 7 years. And while my male cat used the LR without issues, the minute I put a regular non-automated box out for them, he immediately chose the non-automated box over the LR that he used to for 7 years.
My female cat stopped using it years prior to him, and had started pooping on the floor as well, because she didn't like the LR. So I ended up with a Scoopfree (which she grew to hate just as much).
Can't say I blame my cats. I personally hated the LR myself too. While convenient, its not practical health wise. The globe gets nasty inside and its hard to clean. I was constantly cleaning that thing. And it does smell, regardless of their website advertising its odor-free. (And remember - cats noses are way more sensitive than ours. If you don't smell it - they certainly do).
Try putting down a regular plastic litterbox that you have to scoop daily, and I bet your cat will poo in it. Then you'll know that he probably hates the LR like my 2 did. My 2 are much happier now without it. And scooping daily is actually way easier and less time consuming than all the time I spent cleaning the LR each week.
So my expensive LR ended up in the trash, and saved my male cats life. Not even a week after I trashed it, he was almost fully blocked with bladder stones. Had I still been using that automated LR, I wouldn't have known he was having issues pee'ing, because I wouldn't have monitored it daily like I do scooping. I'm now a firm believer in scooping daily vs using automated boxes, so health issues can be caught and treated immediately. So unless you check the LR drawer daily, thats something to think about too.
Last edited by Kattt; 07-28-2010 at 10:24 AM.