I have a portable 40GB external hard drive that I make bootable backup to weekly, but today I'm getting an error when I try to make the backup. When I originally plugged the hard drive in today it showed up fine and I could read and write files to it as always, but when I formatted it so I could make the bootable backup again I got an error. Disk utility said "Disk Erase failed with the error: Input/output error", I've tried with my other Mac and even my Ubuntu PC and gotten a similar message on all of them. Is my hard drive toast, even though it showed up fine before I tried to format it? EDIT: Just tried to format it via Terminal and got "Partitioning encountered error on disk disk2: Input/output error (5)". It's sounding more and more like a bad hard drive.