Hello, fellow MacNNers. My firewire external HDD has 3 partitions, one of which mirrors my primary drive on my PBook using Carbon Cloner. I periodically clone my PBook primary drive to the external drive just for the sake of security but I had never tested if it worked until today. It turns out as I reboot my PBook from the external drive, the computer stalls at the gray Apple logo and would not progress further. I don't know what the problem is. Would anyone please help me out here. THanks.