I tried to format a Buffalo 1TB external hard drive on my Mac today, to HFS+ (journalled). But it failed, over and over again with the error “Volume Erase Failed with the error: The underlying task reported failure on exit”.
It was a brand new drive, already formatted as FAT, so I assumed it was faulty. Turns out, however, there’s a simple reason for it not working: you can’t format HFS+ partitions on certain external hard drives if the boot sector is set to Windows-style “Master Boot Record”. In Disk Utility, when you choose your partition setup, there’s an options button – under which there’s a setting for boot sector. If you choose GUID or Apple Partition Map, you can format without any problems!
