Reformatting from the recovery part

Discussion in 'OS X El Capitan (10.11)' started by blacka4, Nov 17, 2015.

  1. blacka4 macrumors 6502

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    Pittsburgh
    #1
    Guys, i need to do a reformat on my Mac Pro, the Cheese Grater one. When i boot into the recovery, and try and erase my OS and try and reinstall it says I have to use the downloaded app from the app store. Well I deleted my OS and can't reboot to install unless I recover from a time machine backup.

    So I need some help. Apple support was less then stellar. trying to find out why messages won't sign in property and I believe it might be OS related as Messages works just fine on my MBP
     
  2. Shirasaki macrumors 603

    Shirasaki

    Joined:
    May 16, 2015
    #2
    You might need a small data partition to store your install file.
    And from recovery partition you may only be able to install a system by first downloading it and install it.
    Maybe you need a USB installer.
     
  3. blacka4 thread starter macrumors 6502

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    #3
    Correct me if I am wrong but shouldn't the recovery partition include this? It works like that on any other Mac I have ever used
     
  4. Shirasaki macrumors 603

    Shirasaki

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    May 16, 2015
    #4
    No. Recovery partition does not include full system installer. Otherwise it will be gigs large. A typical recovery partition only occupies about a gig.
     
  5. blacka4 thread starter macrumors 6502

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    #5
    ahhh, then my other machines must fetch from the internet to install then. because if on those machines i just erase, and install from the recovery. so i assumed its the same on my pro.
     
  6. Shirasaki macrumors 603

    Shirasaki

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    May 16, 2015
    #6
    You still have other options however.
     
  7. blacka4 thread starter macrumors 6502

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    #7
    and those are??? i'm at a loss...i could do a thumb drive. and i am thinking thats my only option
     
  8. Shirasaki macrumors 603

    Shirasaki

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    May 16, 2015
    #8
    Yep. This is probably the best option if you want to erase your Mac for a clean install. I mean, make a USB install stick to install.
     
  9. DeltaMac macrumors 604

    DeltaMac

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    Location:
    Delaware
    #9
    Download El Capitan through the App Store.
    When the download completes, Quit the installer.
    Make a USB bootable flash drive, or bootable partition to install El Cap when booted from an external drive.
    8 GB is a good size to use for that.
    There's various sites that list a simple terminal command to make the bootable installer, or you can use DiskmakerX app, which makes the process easy.
    Boot to the installer drive.
    If you want to erase your hard drive, you can do that with Disk Utility.
    And, Reinstall El Cap.
     
  10. blacka4 thread starter macrumors 6502

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    Pittsburgh
    #10
    silly question, but can I install from my current OS onto a external firewire Drive then boot from it, and copy OS over??
     
  11. DeltaMac macrumors 604

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #11
    Yes.
    You do need to have the installer to do that.
    And, if you don't have the installer now, you need to download it from the App Store. You don't need to download on the same machine you want to install OS X, but you do need a Mac that is capable of installing that version of OS X.
    For example, I have El Capitan available as a download from the App Store, but my 2008 MacBook won't boot to El Cap, and the App Store won't let me download El Cap on that MacBook.
    At the same time, I can download Lion on that MacBook, but I can't download Lion on my new mini. It has to be compatible before the App Store will let you download.
    Do you have other OS X bootable drives in your MacPro? If you have a different OS X version, you can boot to that, then download El Cap installer from the App Store.

    Whichever method you use to get the installer -
    Boot to the installer. Choose your firewire drive as the destination.
     

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