So I bought a new 1TB Western Digital external hdd to use for Time Machine. I go about reformatting it to Mac OS Extended via Disk Utility but it keeps giving me the error: Disk Erase failed with the error: File system reformatter failed. I try it over and over again after multiple reboots. The only thing that works is just FAT. The drive works fine under FAT, but I obviously need hfs for Time Machine. So I open up Time Machine and I choose the new drive. Time Machine then attempts to reformat it. Then it gives me the error: The underlying task reported failure on exit. I do this again and again with the same errors. I just can't reformat the drive to hfs. What am I doing wrong?