Clean Install

Discussion in 'macOS Sierra (10.12)' started by pitt1717, Sep 10, 2016.

  1. pitt1717, Sep 10, 2016
    Last edited: Sep 10, 2016

    pitt1717 macrumors 6502

    Jul 13, 2007
    any one direct me on how to do this. below there is a thread on usb install but additional steps are needed at the end. I have never had to do those steps.

    can someone post the commands to make a usb installer and let me know if those extra commands are needed. ill try to find the thread again and link to it

    edit: heres the link
  2. RumorzGuy macrumors 6502


    Sep 17, 2008
    Guam, Mariana Islands, U.S.A.
    Are you trying to install on a supported Mac or an unsupported Mac?

    If unsupported, I strongly suggest that you follow dosdude1's tutorial and use his patcher tool.

    Many people -- myself included -- have been very successful at installing the GM -- and previous betas -- on our unsupported Macs in this fashion.

    You will find specific step-by-step instructions here:

    The above link also includes links to dosdude1's webpage -- with instructions -- and to his patcher tool.
  3. tywebb13 macrumors 68020

    Apr 21, 2012
    The additional steps are only for reverting the core storage. This is necessary if you want the recovery partition to show up in the startup manager or edit partitions. This is because the installer often creates a core storage volume without warning.

    If you are not concerned about such matters, you can leave it without reverting.
  4. fruitpunch.ben macrumors 6502a


    Sep 16, 2008
    Surrey, BC
    I assume you have a 16GB USB disk and are able to turn it into a bootable installer.
    But in case you don't want to do that, I thought of a slightly easier way (to me) to do it, particularly if you have only one computer you want to clean install:

    When you boot into the Recovery HD (hold down command R at start-up) you can use disk utility to wipe your drive, and it can also reinstall the current OS version for you.
    So what I did was: first upgrade to the macOS Sierra GM, then boot into the recovery partition, format my OS drive, and then reinstall Sierra on the clean HD.
    Hope that helps!
  5. simonmet macrumors 65816


    Sep 9, 2012
    Sydney, New South Wales, Australia
    The instructions for creating a bootable installer drive are here:

    One thing I wasn't sure of, in Disk Utility there were options for Mac OS Extended (Journaled) and Mac OS Extended (Journaled, Encrypted). Is disk encryption in addition to FileVault and therefore not necessary to have FileVault enabled? Or does FileVault require the disk to be encrypted too?

    Also, it appears that Apple replaces the above disk formats anyway during installation but doesn't give you the choice of (disk) encrypted or not so does it follow the format you originally had?

    I chose Journaled, Encrypted during disk format but if FileVault works without it I probably wouldn't have bothered as it makes you ask for an encrypted disk password every time you boot in addition to your OS X password. A relatively minor annoyance but annoyance nonetheless.

    What if any benefit is there in choosing disk encryption? I have a 2015 rMBP so I'm not too concerned about the (hopefully) minor loss in disk speeds due to encryption but what are the relative costs of disk encryption and FileVault encryption?
  6. tywebb13, Sep 11, 2016
    Last edited: Sep 11, 2016

    tywebb13 macrumors 68020

    Apr 21, 2012
    Apple will only update this page to include Sierra after public release, not before. So at the moment it is only for Mavericks, Yosemite and El Capitan.

    That is one reason I made a thread here on macrumors with the terminal command for the GM and public release of Sierra (which is different to the developer preview and public beta ones).

    Here is my thread with the command for making a bootable usb for the GM and public release of Sierra:
  7. Weaselboy Moderator


    Staff Member

    Jan 23, 2005
    Both methods have the same end result as far as the disk being encrypted, but by doing it through Disk Utility like you did rather than through the FileVault interface in System Preferences you have caused this boot behavior you mentioned with having to unlock the disk each boot. If you had used the FileVault interface it would have integrated that unlock process into the login process. So by just entering your login password, that would also unlock the disk at the same time.

    No real harm the way you have it, just inconvenient is all.
  8. simonmet macrumors 65816


    Sep 9, 2012
    Sydney, New South Wales, Australia
    Sure is!!! I think I may have to reinstall (again!). Groan. Thanks for explaining though.
  9. grahamperrin macrumors 601


    Jun 8, 2007

    The end result will fit Apple's definition of a clean installation. It's not the only approach but at this time (golden master) it's probably the easiest and most appropriate.

    Incidentally: if that cleanliness is followed by (for example) use of Migration Assistant, then technically I should no longer treat the system as clean.
  10. pitt1717 thread starter macrumors 6502

    Jul 13, 2007
    so I made the bootable and installed. all good so far. I checked using the commands diskutil cs list, and no partitions were found. does that mean I am good to go or do I still need to create the recovery partition
  11. tywebb13 macrumors 68020

    Apr 21, 2012
    The recovery partition will already have been created by the installation process.

    The other commands I provided in that thread are for reverting core storage, not for creating a recovery partition. It is optional to revert. If the installation had also created a core storage volume it would hide it from the startup manager. It is still possible to boot up the recovery partition by starting up holding the cmd R buttons. In this case one might revert the core storage to make it show up in the startup manager.

    But if diskutil cs list showed that no core storage volumes were created then you won't have to be concerned for such matters. The recovery partition should already be showing up in your startup manager without reverting.

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