My cat (about 3 now) refuses to use the litter box. He’s trained, but he’ll go right outside the box, not in it.
Right now we have a standard covered box, but before then there was a little hole the cats would go through into a little nook off the side of the house that contained the box.
Any ideas? Could he be claustrophobic? (Do cats get claustrophobic?)
Trained cats NOT using the box can mean a few things.
Yes, he might be claustrophobic. Has he used this type of box before? If so it is unlikely he has spontaniously developed a fear of it. But taking off that cover sure can’t hurt.
Have you recently changed litter types? Going from say a clumping litter that is like soft sand on the feet to a clay litter can be a bit uncomfy on the tosies.
No slam here, but sometimes they can get real pissy if the box gets too dirty.One of ours will let us know when this happens by using the bathroom carpet near our toilet. (Box on other side of bathroom)
Do you have mulitple cats or recently added a cat to your collection? If this is the case put out more boxes in other parts of the house. Sometimes a pussy just needs a bit of privvacy.( 2 cats per box is usually a good ratio)
Lastly, get the cat to the vet to be sure there are no problems. This can be indicitive of an infection or blockage. Especialy if the cat is a male in his sexualy active years. That gland near thier anus, (it produces the nasty smelling spray) can and does get blocked.(yes, even if he is neutered)
In the meantime, keep a close eye on him and if you see him displaying the behavious of elimination, such as sniffing corners and scratching, hi him over to the box yourself and stand over him whist he does his business heaping him with lots of positive praise.
I’m sure more posters will come along to provide you with more info or ideas.
Good luck and give your pussy a snuzzle for me.
I’ll see if the cover is removable on the box, though I might have to get permission from Dad first. He thinks the cat is just out to spite him. 
No change in litter, no addition to the family (just 2 cats), litterbox is clean.
He does often sit down in one spot and sniff the carpet, then start scratching it. I always figured he just smelled something there. I’ll try the praise part, though he’s very secretive (he only goes in the laundry room, where the box is, when there is absolutely no one around). Praise can’t hurt.
Thanks
That’s a possibility too.