Resolved Disk Utility creating wrong partition sizes

Discussion in 'OS X El Capitan (10.11)' started by milaround, Nov 6, 2015.

  1. milaround macrumors member


    Dec 5, 2007
    Pretty straightforward problem:

    1. Partition an external 4TB disk into 2TB/1TB/1TB

    2. Get totally screwed up partition sizes:

    What is going on, and how do I create the partition sizes that I want?
    10.11.1 all software updated to latest.
    Thanks for any help!
  2. Shirasaki macrumors G3


    May 16, 2015
    I remember when I was creating partitions on one of my new hard disks, I saw correct 1.5TB and 500GB, not any weird number. But I did this under an early beta of El Capitan 11.10.0.
    Apple screws this up in official software?
  3. milaround thread starter macrumors member


    Dec 5, 2007
    It appears I have solved the issue; Here's the rest of my journey for anyone else who may have this issue:

    Starting from the above screen shot:

    Tried to re-partition the existing partitions into a single 4TB
    Failed with error:

    Erased main drive, yielded a 4TB partition. Partition map showed a non-removable 0kb "Untitled" partition.

    Proceeded to partition as 2/1/1TB (Note the odd-looking graph)

    The "Untitled" partition is gone, and Disk Utility shows the partitions correctly on the graph, but is missing a partition on the list.

    Quitting/Restarting Disk Utility now shows the previously missing partition. All seems well from this point.
    Seems like buggy native software. Sad to see... I will report back if something goes wrong.
  4. ataractic macrumors newbie

    Sep 10, 2008
    --- Post Merged, Oct 12, 2017 ---
    I've seen similar issues repeatedly when trying to partition disks using disk utility in El Capitan. I'm not sure when this bug was introduced, but it is very concerning to see a something as essential as disk utility apparently not being tested enough before release. I guess the focus is shifting more and more to shiny new features rather than the core OS. I use terminal to partition my disks now. Sad indeed...

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3 November 6, 2015