In device Management on common services I'm getting duplicate devices.the same no of devices are seen twice with the management IP (loopback IP address).what could be the possible reason.
Till yesterday it was fine i dont what gone wrong?
You need to delete the duplicates from DCR first. That is, go through DCR, and remove those duplicate entries which you do not want. Then, run a new Discovery, and see if the deleted duplicates come back.