Locked hard drive

I am wondering if it is because you do not have the user accounts on the machine that have encryption. Can you drop an image with a user that originally had access on it?

We have had user forget the FileVault keys..

See what you can do..

But if all else fails, then you can:
Boot from another disk, and use disk utility to reformat the HD -- loosing all it's contents in the process..
-- But you will end up with a disk that you can do a fresh install on..
-- So that's a "last resort" solution..

Thanks for the responses, however my problem is that the encrypted drive is locked. I booted from a thumb drive with the OSX image, but when I try to run disk utility to reformat the drive, the partition is locked and I don't have a password to unlock it.

Sorry, I needed to be clearer: In the case where you decide to erase the HD.

You will need to re-partition the HD - since the OLD partition is locked.
But it can be blown away, and replaced by a new partition.
( This process still preserves security - since the old data cannot be accessed )
( But you do end up with a machine that is useable one again.. )

So Boot from an external, Repartition the internal, Reformat the internal, then Re-install...

Partition Map Scheme should be: GUID ( = OS X Standard )
( The old apple one was for pre-OS X days )

-- Regards
-- Peter

I did a little more research and found the instructions to fix my problem. I had to use the Disk Utility cli command to delete the logical volume group, then I could reimage the drive. http://derflounder.wordpress.com/page/2/?s=filevault

All you need to do is exactly what @PeterClarke mentioned, repartition the drive to a single partition. We do this literally everyday on FileVault 2 encrypted systems without first unlocking the drive. We have a single line command as part of our DeployStudio workflow that flattens the drive before starting the imaging. Never fails to work as far as I've seen.