I've looked and can't find a fix. My old roommate's iMac was set up to use Back to My Mac, on it, and this iMac shows up under shared drives on my Air. I've moved out and don't share with this computer any longer, but I forgot to disable it on the iMac. I know if I turn back to my mac off, under iCloud, it removes it, but I don't want to leave it off. Does anyone know of a way to remove this iMac that I no longer have access to? Thanks!