External hard drive disconnected during reformat: now will not format

disk-utilityexternal-diskpartition

Using disk utility, I was erasing and re-formatting to FAT. During that process, the usb cable was removed. Now, the hard drive will not format. When recognizing the hard drive, a window shows up stating "The disk you inserted was not readable by this computer" with the options to "initialize; ignore; eject." "Initialize" does not seem to do anything.
Disk Utility shows the physical drive, but no sub folder (volume?) When attempting to erase and create a new partition, I get an error.
The disk was already empty, so I'm not worried about retrieving files, but is the drive itself physically damaged?

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Best Answer

You could try overwriting the partition table with zeros. To do so, enter sudo dd if=/dev/zero of=/dev/disk3 bs=1m count=1 in a Terminal window. This will overwrite the first megabyte of the drive with zeros, which will include (and thus erase) the partition table (or its remnants). Remove and re-insert the drive; if everything goes well it will tell you that the disk was not readable and it'll offer to initialise the disk. (I tried this with an old USB stick a minute ago and it worked fine.)