That's what I got when I tried to partition my new WD MacBook HD. I installed the drive, started up with the OSX Install Disc, and opened Disk Utility, selected Partition, 1 partition, and Mac OS Extended, then clicked "Partition," but no dice. Does this mean that there's something wrong with the new drive? I am installing the drive because my computer fell on the floor, and the old drive appeared dead. I took it to the Genius bar, and they successfully booted it using an external. Thanks!