So the background is that both my roomate and I each have a cat. The cats have lived together for a long time and get along etc. My roomate's cat has his litterbox in my roomate's bathroom and Snow, my cat, has her litterbox in my bathroom. Up until the past two weeks, each cat would use their individual litterbox without any problem. Two weeks ago Snow started pooping on the floor of my roomate's bathroom. Snow still pees in her own litterbox in my bathroom, but poops in my roomates bathroom floor! What's even weird is that she only does this when nobody (me or my roomate) is home, because when I/roomate are home, she poops normally in her own litterbox. I would appreciate any help because I just don't know what to do. I have not 'caught' Snow in the act to teach her 'no'. I have tried thinking of anything that has changed in the past several weeks that would cause Snow to do this, but I can't think of anything different (no changes in litter, food, environment, etc....). I don't know what else to do! Please help!!