7 Replies Latest reply: Aug 28, 2014 6:41 AM by scorty3
pinkyd Level 1 (0 points)

I have a 3TB Hardisk for my 27 inch iMac. I have added a partition to the current Macintosh HD and divided the storage space to :


1. Macintosh HD - 1 TB - Mac OS Externded (Journaled)

2. New HD - 2 TB - Max OS Extended (Journaled) ( Use as Storage for working files and resources )


The Macintosh HD already have softwares and programmes installed. Reading from other sites, I can partition even there's data on it because it will just dividethe drive into 2. So I use Disk Utility > just click on the add "+" button to divide Macintosh HD to above partition. But the options button is greyed out. After that a message appears " Click to Apply to apply changes. To make more changes you must first apply this change ".

After clicking apply, the partitions have been divided to two but I could not add another partition for New HD.


Is there a maximum partition for the HD? Or does this problem occur because I already have data on the original Macintosh HD?

iMac, OS X Mountain Lion (10.8.2)
  • putnik Level 3 (780 points)

    It is hard to understand what you have done. Do you now have three partitions and want a fourth?  Remember there is a Recovery partition inside the Macintosh HD partition already.


    Perhaps you should run the following command in Terminal and then select "Show every partition" in the Debug menu of Disk Utility.  It may tell you more about the situation.


    defaults write com.apple.diskutility DUDebugMenuEnabled 1

  • pinkyd Level 1 (0 points)

    I have only 2 partitions and I can't add the 3rd.

  • putnik Level 3 (780 points)

    The option +/- buttons are greyed out until you move the pointer focus and click in the partition concerned.  You can also resize the partitions until you have what you want.  There is an option to "revert" so, at this stage, you can back out if you want.

  • pinkyd Level 1 (0 points)

    Screen Shot 2013-04-08 at 7.15.14 PM.png


    I have click the partition that I would like to partition and the '+' is still greyed out.  Back to my previous question :

    Is there a maximum partition for the HD? Or does this problem occur because I already have data on the original Macintosh HD?

  • Radiation Mac Level 5 (4,645 points)

    I believe you have to re-partition the "entire" hard drive the way you want it, in this case with 3 Partitions that you would initally set up..  You cannot repartition just an exisitng partition into multiple partitions that I am aware of.

  • keg55 Level 5 (7,706 points)

    You have a Fusion Drive as evidenced by the Type: Logical Volume Group in your screenshoot. You can ONLY add 1 additional partition which you have done. Below is from Apple' About Fusion Drive.


    Can I add a partition to the hard disk with Fusion Drive?

    Using Disk Utility, you can add one partition to the hard disk on Fusion Drive. Once you add the partition, the "plus" symbol in Disk Utility to add additional partitions will be grayed out. You cannot partition the Flash storage.

  • scorty3 Level 1 (0 points)

    try to resize the partitions