External USB HD help!

[xiaoxu5101]

When a message that "this disk have no volume that Mac OSX can read" appear after I plug my usb hard drive in, is that mean I need to format my hard drive. What is the correct way to format a hard drive in Mac OS X. I am using Disk Utility to erase the hard drive. Is this correct? Now the Disk Utility is still running and it gives a message "Unmounting old volume". So is the Disk Utility formatting my hard drive? How long does it take? It seems have been running for a long time. :(

I hope there will someone help me to solve this problem. Thank you.

[Buzz]

Disk utility is the tool to use. The disk must be unmounted to format. And it may take a while depnding upon the drive size. USB is the slowest interface available, that will also slow down the formatting.