# Macos – OS X: can’t create a partition because drive is locked

installationmacospartitioning

Problem:
I have a USB key with Mountain Lion on it and I want to install it on my MacBook Pro. I deleted the existing partition on the laptop and wanted to create a new one where to install the OS but can't because everything in the partition tab for the drive is grayed out.

Basically, I can't do anything until I unlock the partition. So the question is: how to unlock a partition from disk utility or the command line?

#### Best Answer

I looked first hand into this problem and the following commands unlocked and formatted the disk, although Disk Utility could not.

$diskutil list  Should show something like this: /dev/disk0 #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme *121.3 GB disk0 1: EFI 209.7 MB disk0s1 2: Apple_HFS Macintosh HD 120.5 GB disk0s2 3: Apple_Boot Recovery HD 650.0 MB disk0s3 /dev/disk1 #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme *64.0 GB disk1 1: EFI 209.7 MB disk1s1 2: Apple_CoreStorage 63.2 GB disk1s2 3: Apple_Boot Recovery HD 650.0 MB disk1s3  Then format the disk in question. In this case, disk1. $ diskutil eraseDisk JHFS+ name disk1


You should see this:

Started erase on disk1
Unmounting disk
Creating the partition map
Waiting for the disks to reappear
Formatting disk1s2 as Mac OS Extended (Journaled) with name name
Initialized /dev/rdisk1s2 as a 59 GB HFS Plus volume with a 8192k journal
Mounting disk
Finished erase on disk1


The following web pages helped me figure this out and might be of use to somebody else.

https://discussions.apple.com/thread/4091299?start=0&tstart=0

http://derflounder.wordpress.com/2011/11/23/using-the-command-line-to-unlock-or-decrypt-your-filevault-2-encrypted-boot-drive/