The other day, well today to be precise, I was interested in creating a TrueCrypt encrypted volume on a USB Drive. However, TrueCrypt will not let you perform Volume Encryption on a drive that contains existing partitions. I attempted to delete all of the partitions from the volume using Disk Utility, but it never worked. An examination of the drive using diskutil revealed the cause:
$ diskutil list disk3 /dev/disk3 #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme *32.0 GB disk3 1: EFI 209.7 MB disk3s1 2: Apple_HFS Untitled 1 31.7 GB disk3s2
I had previously installed Mac OS X on this drive and any boot drive for a Macintosh now needs an EFI boot partition. Unfortunately, you cannot delete that partition using Disk Utility (at least I don’t know how). So, to completely remove all partitions from the drive, you need to use: gpt (GUID Partition Table maintenance utility).
I first deleted the Untitled 1 partition using Disk Utility, then I removed the EFI partition using this command:
$ sudo gpt remove -i 1 disk3 disk3s1 removed
That left me with an unpartitioned volume:
$ diskutil list disk3 /dev/disk3 #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme *32.0 GB disk3
Hopefully you won’t get as frustrated as I did trying to find this.
