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?
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
