11 Replies Latest reply: Jul 31, 2014 9:52 AM by zynjulia
Swift1113 Level 1 Level 1

Hi all,


I just received a new Mac Mini today that has the 1TB Fusion Drive installed.  After successfully migrating all of my files to it, I went to create another Mac partition on the Fusion Drive.  Towards the end of the partioning process, an error of 'invalid request' occurred and I am now left with a large chunk of the drive that is classified as 'Free Space'.  Oh well, no worries right?  Just format the free space, right? 




Disk Utility is not letting me do ANYTHING with 340GB of 'Free Space' anymore.  If I choose to format it to any format, click 'Apply', and then click 'Partition', Disk Utility flashes the words 'Preparing to partition disk...' and then just does NOTHING.  Everything is greyed out as well in terms of the 'Options...' button.  I have tried every possible option that Disk Utility offers with no luck at all. 


So basically I am just completely stuck and can't access that 340GB of Free Space anymore.  I tried to restart using Command-R and doing a repair disk that way but Disk Utility just says the partition map is fine and doesn't report any other errors during the repair or verify disk processes.  I'm not opposed to just blowing the entire Mac away and restoring it back to factory condition, but can I even do that?  Won't it just revert OS X back to its original state but leave the partitioning untouched?


Does anyone have any advice?  I have never seen Disk Utility error out during a partition operation and have certainly never seen behavior like that before.  I read somewhere that Macs with the Fusion Drive have a special version of Disk Utility and I'm wondering if this version just isn't stable? 


I'm totally stuck and would appreciate any help anyone might be able to offer.


Thank you!

Mac mini, OS X Mountain Lion (10.8.2)
  • den.thed Level 7 Level 7

    Startup from your Recovery Partition and then in two steps, see if you can 1) remove the second partition by selecting 1 partition, then 2) drag the partition divider down to add the space back to the first partition and click apply.

  • VikingOSX Level 6 Level 6
    Mac OS X

    A little light reading from Apple on the Fusion Drive. FYI.

  • Swift1113 Level 1 Level 1

    Thanks for your reply.  Unfortunately it is not allowing me to remove the unpartioned space.  The minus button is greyed out and when I hit the plus button, all it does is pop a little partion block called 'Untitled2' in to the partion map but I am unable to format or do anything with it.  I'm also not able to resize anything via clicking and dragging or manually changing the numerical value.  Everything is greyed out.


    I am attaching a screen capture of what my disk utility window looks like for the hd partition tab in case that helps at all.



  • den.thed Level 7 Level 7

    Awesome VikingOSX, I hadn't seen that and owe you a tall frothy one.


  • BDAqua Level 10 Level 10

    Did you try highlighting the bottom space there?

  • Swift1113 Level 1 Level 1

    Thanks for the article, Viking.  I saw that about a week ago, but no updates there that pertain to my particular issue.


    At any rate, I was able to resolve this last night.  Since something was messed up with the partition map, I decided to add a 3rd partition to see if it would even let me.  Once the 3rd partition finished creating, I now had 2 partitions (the new one having claimed all of the free space as its own somehow).  It was then a simple matter to merge the two partitions back down to one large one.  So now I am back to square one and too afraid to try to add a partition back to this drive  :-P


    Oh well, at least I reclaimed 340GB of of my HD that was in no man's land...


    Thanks everyone for your suggestions.

  • VikingOSX Level 6 Level 6
    Mac OS X

    Cool. A happy ending.


    Good Luck.

  • T'Lai Level 1 Level 1

    I had exactly that problem with my new iMac. Thank you so much for posting your fix! Is there any way you could go back and label this thread as solved so that anyone else with this problem will know you found a fix? Thanks!

  • Swift1113 Level 1 Level 1

    Hi T\'Lai,


    I'm glad that this thread helped you troubleshoot your issue, however, I hesitate to mark this one as 'Solved'. 


    In the end, I am stuck with two partitions with sizes that I ultimately did not choose myself.  I was forced to accept the 'useable' partition map and was not allowed to adjust it at all.  While I intended to have a Windows partition of only 180GB, I am now forced into it being 340GB for no reason. 

  • T'Lai Level 1 Level 1

    Interesting. I actually merged all partitions back into one single partition. I decided that I didn't want to repartition it until Apple comes out with some kind of firmware upgrade to fix the fusion drive issues, but as far as DU goes, everything looks like I could repartition it into two parts of any sizes I choose. It would mean redoing your windows side, but you should be able to do the same thing. I don't blame you if you don't want to do that though, in theory, it shouldn't be necessary.

  • zynjulia Level 1 Level 1

    Hi Swift1113 and T'Lai, i have this prob also, but i couldnt get it resolved by adding a new partition. After adding the partition, the images shows that it seems to claim the grey area, but the numbers dont add up. And if i click -, it goes back to the original setting, with the same grey partition listing there... so i am wondering if there is anything else i may be missing? Thanks