I found myself having to get on a plane today and travel 1,000 odd miles to get about a terabyte of data. Given the importance of the task, I opted for brand new drives so I dashed to the store and picked up two 3 terabyte Toshiba hard drives and I wanted to verify that they worked prior to travel. I plugged them in, turned them on and then found that I could NOT write to them. Digging further into this showed me that they were NTFS and on OSX, NTFS is a read only partition type. So I tucked into Disk Utility only to find that it could not destroy the NTFS partition. Sigh. Happily there’s always the command line and with Jared’s assistance, I came up with this:

diskutil eraseDisk fat32  TOSHIBA\ EXT /dev/disk3

diskutil is the command line version of Disk Utility and it is both infinitely more capable and infinitely more dangerous. To get started with this, do a:

diskutil list

which will give you a list of all mounted discs. DO NOT. I repeat DO NOT use this on anything other than the disc you want to erase. This told me that I wanted to erase /dev/disk3. You’ll also need to find out the format you want to make the new disc. And you can do this with:

diskutil listFilesystems  

Finally you have to bring it all together by specifying the current name of the disc as a way of preventing you from erasing something important. And that gives us the final command or:

diskutil eraseDisk fat32  TOSHIBA\ EXT /dev/disk3

And then a little bit of wait and you have a brand new, writable disk.


Fat32 has a 2 gigabyte per file limit. So just ignore every single bit of what’s written above. Sigh.