DiscUtility and FileVault2

On my MacBook (which is now running OS X 10.7 Lion), I set up FileVault 2 to do whole disk encryption, as I’ve always been a little concerned about the possibility of a laptop going missing when travelling and the consequential danger.  Since running Lion, the MacBook although rather old being a late 2006 model, has been very stable.   (A lot more stable than some years ago when I experimented at some cost with using PGP Whole Disk Encryption – but that’s another story.)

However, a week or so ago the MacBook become unresponsive and I needed to power it off and reboot.  Whenever I have to do such drastic measures on my Macs, I always run Disk Utility afterwards on the system disc and any other drives that were connected at the time.  Mostly these verify with no problems.  On this occasion the verification reported the need to repair the drive.  As one can’t repair the drive on which one is running I did as was instructed and rebooted in to the recovery partition (hold command-R when booting).  Running Disk Utility from the Recovery Partition on the System Drive set to repair ran for a while but then reported that it couldn’t repair the drive.  I wasn’t too worried by this as I had a SuperDuper cloned backup from about a week before (and I don’t do a lot of work on the MacBook these days), and also an almost up to date Time Machine.  

However, before attempting to reformat and rebuild I thought I would try booting from my BackUp and running Disk Utility from there.  This produced the same result as Disk Utility on the recovery partition — couldn’t repair.  It was at this point that a bit of web searching revealed the need to unlock the encrypted drive (which I suppose is obvious when one thinks about it — but there was no suggestion from Disk Utility that one should do this).  

On Disk Utility under the File menu there is an option to Unlock the drive.  This produced a password prompt.  At this point I wasn’t really sure what password was required but I had stored in 1Password accessible on my iMac, the “Master Password” for the encrypted drive.  (Later reading other articles, it would seem that a password for any authorised account on the machine would also work.)

Anyway, this enabled Disk Utility to do its repairs and get the system drive up and running again smoothly.

Here is a useful post from Der Flounder on the same topic.

It would really have helped if Disk Utility gave some hints that the drive needed to be unlocked.  It would appear that I might also have got stuck with re-installing as well, and repartitioning also requires the drive to be unlocked.

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