I have some trouble with my partitions on my Macbook Pro. I created 2 partitions. One named "Yo" where I have installed Yosemite release. Another one named "Save" where I put all the stuffs I need to keep secure for work.

I want to create a 3rd one to re-install Mavericks just because one of my app is not working on Yosemite.

The trouble is that I can't do it through the Disk Utility GUI because everything is disabled. I saw a post here where they talked about using diskutil command in the terminal. I tried to follow it but I have something weird when I try to list all my disk. Here is the output:

$ diskutil list
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *251.0 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:          Apple_CoreStorage                         224.9 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
   4:                  Apple_HFS Save                    24.5 GB    disk0s4
   5:                 Apple_Boot Recovery HD             650.0 MB   disk0s5
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                  Apple_HFS Yo                     *223.3 GB   disk1
                                 Logical Volume on disk0s2

What I want to achieve is having these 3 partitions:

  • "Yo" -> 180GB
  • "Mavericks" -> 45GB
  • "Save" -> 25GB

Is that achievable without having to reinstall Yosemite and if so how can I succeed to do that?

  • Apart from the fact that the Yosemite installer seems to make a CoreStorage volume, this isn't really a question about Yosemite. CoreStorage has been around since Lion I think and this problem could arise in other situations. It should be simple enough to reword it without Yosemite references. – Michael D. M. Dryden Aug 23 '14 at 23:01

The problem is that the Yo volume is inside a CoreStorage logical volume group. You can manipulate them from the command line, but the easiest thing to do is just revert it to a normal partition (in the terminal):

diskutil coreStorage revert /dev/disk1

This shouldn't cause data loss, but as always when working with partitions, back up anything you can't afford to lose. Once it's a normal partition, you should be able to manipulate it in Disk Utility again.

See man diskutil for more information.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .