I want to completely wipe a USB thumb drive, re-partition it, and reformat the partition as ExFAT, not JHFS+. Unfortunately, I used FileVault 2 on it when I made it and that seems to be preventing me from destroying the partition table on the drive now.
In the Disk Utility app I can't save and partition table changes to the drive and I can't format the existing partition as anything that isn't HFS+-based.
From the command line this is what I see:
> diskutil list /dev/disk6 #: TYPE NAME SIZE IDENTIFIER 0: Apple_HFS UntitlesHFS *14.8 GB disk6
And when I try to erase the disk:
> diskutil eraseDisk ExFAT Files disk6 Unable to begin erase operation: Placing a partition map on a Core Storage logical volume is not supported (-69671)
I can't erase the volume, obviously, because ExFAT wouldn't work with FileVault 2:
> diskutil eraseVolume ExFAT Files /Volumes/UntitlesHFS The specified file system is not supported by Core Storage for use on a Logical Volume
I do know the password for the drive and can mount it just fine.
How can I wipe this USB drive, repartition and reformat it as ExFAT?