Twice in as many weeks, I’ve had a Mac come across my desk with the disk hosed up. I mean really hosed up. In these cases, we give people a new computer, help them migrate whatever we can, then redo the old computer (it takes less time). But, in both of these cases, the hard drive has been encrypted with FileVault2. Now, that isn’t a problem (I had the passwords) but by this point, I just wanted to blow everything on the drive away and do a reinstall of everything.
But, if the disk is encrypted with FileVault2 (aka a Core Storage Volume) you can’t mess with it from disk utility. Even if you unlock it. You have to go out to the command line.
The first time I really hosed the disk and had to erase it (which you can do). The second time, I was able to simply erase the Core Storage Volume.
This site was where I found the commands: http://blog.fosketts.net/2011/08/05/undocumented-corestorage-commands/
I’m posting it here to help me when I need it again.
Image from Antimidia via flickr