I was able to login to all 10 cameras and factory reset all 10. Once they rebooted, they plug and played to the NVR and allocated the NVR login/password to them. Perfect.
@alastaristevenson. I just purchased a house and it has an HIKVISION system installed. The previous owner factory reset the NVR - YAY!!! But of course did NOT factory reset the 10 cameras attached to the NVR. I tried the Hikvision Password Reset Tool with no luck on 9 of the 10 cameras...