Need help with MacOSX reinstall

Discussion in 'OS X El Capitan (10.11)' started by genivn, Jul 12, 2016.

  1. genivn macrumors newbie


    Jul 12, 2016
    Can someone help?The partition tab is greyed out, and what do i need to do to split this hard-drive to 2 partitions, for dual-booting Windows and Mac OSX
    Mac Pro
  2. Shirasaki macrumors 604


    May 16, 2015
    Format the entire disk. Format it to a single partition, install Mac OS X, and then use boot camp assistant to install windows you want.
    This is what I will do if I were you.
  3. JohnDS macrumors 65816

    Oct 25, 2015
    Shirasaki is right. That is your only viable alternative. Make sure that you back everything up first.
  4. Fritz5484 macrumors newbie


    Jul 30, 2014
    United States
    This question is probably so basic, it's almost embarrassing. Anyway --- like the OP, I also need to completely wipe my SSD boot drive (El Cap 10.11.5) and perform a clean install with a pre-formatted USB installer. In my case, I only have one partition: the standard "Macintosh HD."

    My question involves the use of Disk Utility at the "erase/format" step. After I boot into Recovery Mode and open Disk Utility, do I erase and format ONLY the "nested" partition ("Macintosh HD"), without touching the "un-nested base" of the SDD?

    Alternatively, should I FIRST erase/format the "un-nested" base of the SSD ("APPLE SSD SM0512G Media")? And then, once erased, format the (presumably) blank SSD as a drive with a single partition, titled "Macintosh HD"?

    Thanks in advance for any feedback.
  5. JohnDS macrumors 65816

    Oct 25, 2015
    Fritz, you really should start a new thread, rather than asking a fresh question in someone else's.

    Having said that, all you have to do is to boot into recovery mode, then in Disk Utility, select Macintosh HD and reformat it to "Apple Extended Format (Journalled)". Then quit Disk Utility and click on Install Operating System. This will install a fresh OS (it may take hours). You don't need a preformatted USB installer.
  6. Weaselboy Moderator


    Staff Member

    Jan 23, 2005
    Either way will work in your case since there is only the one visible volume (Macintosh HD) on the drive. Just select either one from the erase tab and the end result will be the same since you are booted to the USB key installer.

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