How can I *unlock* a CoreStorage logical-volume without mounting it?

Question

I had a damaged disk that's encrypted with CoreStorage / FileVault. DiskWarrior was unable to operate on it while encrypted, obviously (“This is an offline, unavailable Core Storage disk.”); but the diskutil corestorage unlockVolume [UUID] operation both unlocks and mounts the volume.

With a damaged disk like this, I'd really like to avoid mounting the filesystem before working on it — I'd just like to unlock it so I can proceed with recovery tools.

Is there any way to enter the disk's password without causing it to subsequently be mounted by OS X?

Answer 1

diskutil corestorage unlockVolume has a -nomount option that you can use to achieve this exact effect.

Answer 2

Click the Unlock button in the top-right of DiskWarrior and enter the password to unlock the volume