Q: External HDD Unlock

I have the same problem but with my Macbook Air's internal SSD. So basicaly, i cannot install Mountain Lion on my computer. I'm looking forward to a solution.

I wanted to erase my (encrypted) partition and make a new (encrypted) one. Then I got a failure message, the partition was gone and well like I said, I cannot make a new one.

I'm having this exact problem. All options are grayed out in disk utility

I have found a fix that worked for me. I booted from the recovery disk, from there I could still see my partition. I erased it an made a new one.

My source:

http://derflounder.wordpress.com/2011/11/23/using-disk-utility-to-unlock-or-decr ypt-your-filevault-2-encrypted-boot-drive/

Good luck!

Luckily I have another Mac and was able to boot the problem Mac into target disk mode and run disk utility on the working Mac. Was able to erase the partition no problem then. Mountain lion installing now. Hopefully you can find access to another mac

I got the same problem with my external HDD (with 2 partitions) while I was using one of the encrypted partition as Time Machine backup. I could not erase it after I upgrade to Mountain Lion, and it shown "this patition contain a locked disk and can not be resized until it is unlocked" in Disk Utility.

Finally I get it fixed by the "diskutil" command in "Terminal" in "OSX > Applications > Utilities".

I used the command "diskutil" to verify the UUID of the "Logical Volume Group (LVG)" of the locked partition.

Then use the command to delete the LVG.

** All logical volume under this groiup will be deleted!!

Once the operation finished, I am able to recreate the partition in Disk Utility.

Hope this help!!

This solution is a much better approach than grabbing the disk and using a partition tool on another machine. Thank you, worked for me. (This is for the solution Eddie Yam posted.)

Eddie's solution worked for me too. Took me about an hour to find this thread, and 2 minutes to regain access to my HD. Thanks!

My apologies for "hijacking" this thread but looks like you all know what you are talking about and I have searched the web for over an hour without finding a solution to my problem. Maybe Eddie Yam can help me.

I had an external HDD where I stored encrypted secondary backup of my iMac. After upgrading the iMac to Mountain Lion I brought the HDD from remote location to update the backups on it. Time Machine stated there is not enough room in the volume, so I just went to Disk Utility and erased it. I am very well organized and I knew I could just wipe the disk clean as I have another functional backup. Not so smart. Now I have the external HDD mounted but I can't use it for back up and I can't reformat or repartition it. (see below)

It states that "This partition contains a locked disk and can not be resized until it is unlocked" I tried to used the method Eddie suggested but I get the following:

I appreciate your help in unlocking my external HDD and making it useable again. Thank you.

According to the screenshot attached, the UUID should be the long string follow by "Logical Volume Group", which is "6B88...8BE2", let's try to amend your command by replace "UUID" to "6B88...8BE2".

Hope it helps!

Thank you Eddie, that helped. Also, I was using the wrong command, I had to type in "diskutil corestorage delete 6B885E57-6D7E-4CB6-B2AA-507DD9A58BE2" Thank you very much for your quick reply.

You saved my 1.5 tb external HDD. Thanks.

hi this is the thred ive been looking for, for two days. Eddie im a super noob and so good with termial can you send me a list of commands to use to reclaim my harddrive. its a seagate 1tb external and im pretty sure i deleted a partion or something in it because now all it says in disk utility is Expansion and i cant mount or format or partion please help ive included a screen shot.