Yes, I've noticed that this question has popped up before. I'd like to share my situation, too, though. I have a 3 year old neutered male cat who lives exclusively indoors, and a 6 year old spayed female cat. Last year, I took the male cat with me to my apartment in college, but now that I've graduated, the cat is back to live with me at home with my parents. He never used to spray, it wasn't a problem even one time. The problem is that the two cats don't like each other, the female cat ESPECIALLY hates the male cat, and in return, the male cat will chase the female cat around the house almost every morning. Now, we've caught my male cat in the act, and it's frustrating to know how to react. My dad has even thrown a shoe at him which I told him won't resolve the problem. I'm not interested in putting the cat outside, especially because there are coyotes where I live.
spray him with water, doesnt kill to try at least....hope it works, good luck,
I had a cat with this same problem and unfortunately we had to get rid of him because we couldn't take the peeing any more. Here are some things i did that helped, first off you need at least 4 litter boxes. They don't have to be huge but a cat needs at least 2 different ones to use and since you have 2 cats thats 2 boxes a piece. Also clean the boxes every 2-3 days if you let stuff pile up in them the cat won't want to use them. Also i purchased a carpet cleaner with an enzyme in it to break down the protein in cat pee so it won't smell as appealing if he wanted to mark it again. You can google it and find lots of carpet cleaners just for cat pee regular resolve and stuff don't work because cat pee has protein in it that makes it stink. ALso don't leave anything on the floor, no socks, towels, shirts ect.. if i did this my cat peed all over the item in question. Also try getting some calming room spray or a plug in cat calming spray that helps de-stress your cat. If you have other indoor pets like a dog or other cats separate them. Marking is usually a dominance thing and the cat who marks is claiming his territory. In the end i tried for 5 years to break my orange tabby of his peeing problem but he just wouldn't quit i had to re home him. Best of luck to you and i hope it works out for you and your kitty.
Had a neutered male and a spayed female that had the same issues.
Spray bottle and booby traps