Formatting an external hard-drive for Mac & PC

Discussion in 'Mac Basics and Help' started by ana28, Apr 16, 2016.

  1. ana28 macrumors newbie

    Apr 16, 2016
    Hi All,

    I have having problems in regards the process of formatting my external hard-drive. I am trying to partition my hard-drive so it can be read on both Mac and PC. However, the partition option remains greyed out for my hard drive and when I place the cursor over the greyed out partition option, it states that "Disks with Masterboot record partition maps cannot be partitioned.

    What are my options to resolve this issue?

  2. Weaselboy, Apr 16, 2016
    Last edited: Apr 16, 2016

    Weaselboy Moderator


    Staff Member

    Jan 23, 2005
    Just jump over to the erase tab in Disk Utility and you should be able to format it how you want from there.
  3. rigormortis macrumors 68000


    Jun 11, 2009
    If you want read and write on an external hard disk on both the windows and Mac platforms, the best solution is to use EXFAT.

    If you want to do a time machine backup or you want to be able to do a Windows backup to it, then I don't think EXFAT will work
  4. jsavvy macrumors member


    Aug 19, 2011
    EXFAT is probably best, but rigormortis is correct, you can't use it for a time machine destination. Also, don't forget to unmount your drive before partitioning it.

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3 April 16, 2016