Clean install of HS from USB with HFS+

Discussion in 'macOS High Sierra (10.13)' started by danielkun, Nov 3, 2017.

  1. danielkun macrumors newbie

    Mar 15, 2014
    I want to use Boot Camp to be able to dual boot into Windows. I've already tried to do a clean install but Windows won't find the partition if installed with APFS and Windows also becomes the default partition which is annoying. Apples response to this was to hold down the option key on boot.

    I read that it's possible to to an upgrade to HS and keeping HFS+ by adding an argument to the update command. How is this done when doing a clean install from a USB memory?

    Or do I have to install Sierra first and then run the update command (with --converttoapfs NO) to get a fresh HS install with HFS+ ?
  2. Fishrrman macrumors P6


    Feb 20, 2009
    From my archives:

    MacOS High Sierra includes the all new APFS file system, which is arguably one of the most significant new features introduced in the new Mac operating system update. Nonetheless it’s possible that some Mac owners with SSD volumes will want to not convert the existing HFS+ file system to APFS file system when installing macOS High Sierra. With a little command line magic, you can skip converting to APFS during the macOS High Sierra installation process if desired.

    How to Install macOS High Sierra Without Converting to APFS File System

    This is not recommended and should only be applicable to advanced users who have specific reasons to not want to convert a Mac to APFS. APFS is faster and offers better encryption, amongst other benefits, so it’s generally recommended to use APFS if the Mac supports it. APFS is currently only supported on SSD drives, with Fusion drives support for APFS soon to arrive in a future Mac software update.

    How to Not Convert to APFS During macOS High Sierra Installation

    By skipping APFS conversion of file system, macOS High Sierra will install with the longstanding HFS+ file system instead.

    1. Download the MacOS High Sierra installer from the App Store as usual, making sure it’s within the /Applications/ directory*

    2. Open the Terminal application, found in /Applications/Utilities/ (or from the Utilities screen menu options if booted from a USB boot installer)

    3. Enter the following command syntax at the command line prompt:

    /Applications/Install\ macOS\ High\ --converttoapfs NO

    4. Hit return key to start the macOS High Sierra install process with the –converttoapfs NO directive, thereby skipping the APFS conversion of existing file system

    * You will need the full installer to have the Contents/Resources/ options available to you. You can download the full macOS High Sierra installer with these instructions if you’re getting the little mini-installer without /Content/Resorouces/ folder.

    In case you were wondering, skipping APFS can be achieved when running the High Sierra installer directly from Mac OS or when using a macOS High Sierra boot installer drive.

    Mac users who ran the beta of macOS High Sierra may remember earlier versions of the beta builds had a toggle setting during installation to skip APFS conversion, but that option toggle is no longer available in the installer.

    Regarding APFS and macOS High Sierra, Apple says the following on a knowledge base support article:
    “When you install macOS High Sierra on the Mac volume of a solid-state drive (SSD) or other all-flash storage device, that volume is automatically converted to APFS. Fusion Drives, traditional hard disk drives (HDDs), and non-Mac volumes aren’t converted. You can’t opt out of the transition to APFS.”

    Despite the Apple support article saying that you can’t opt out of the transition to APFS, it turns out that you can skip APFS if you choose to start the installer from the command line of Mac OS and give a directive to skip file system conversion. Outside of using the Terminal approach outlined above, or installing on an HDD or Fusion drive, there is no known other method to skip APFS.

    Again, there is no benefit or particular reason for most users to skip APFS conversion. Skipping APFS file system on a Mac with a flash drive means the computer won’t see the potential performance boost offered by APFS with High Sierra. This is really only for advanced users who need to skip APFS for a specific reason, usually for networking or drive sharing compatibility purposes.
  3. danielkun thread starter macrumors newbie

    Mar 15, 2014
    Thank you! This assumes I'm on Sierra and want to upgrade however.
    I'd like to do a fresh install from a USB memory
  4. Fishrrman macrumors P6


    Feb 20, 2009
    "I'd like to do a fresh install from a USB memory"

    I suggest you follow the instructions above, and do this:
    (this assumes your target drive was previously initialized to HFS+)
    1. Create your USB installer
    2. BOOT from the USB install drive (It will open to the installer)
    3. DO NOT run the High Sierra installer yet, instead...
    4. ... Quit the installer and open terminal.
    5. Enter the following command:
    (you're going to have to type this one in by hand -- be careful of where the space characters are! I have used an "underscore" in the line above to indicate where the space characters are. Each underscore represents a SINGLE space. There are no "doubles". Remember to enter "spaces" and not "underscores" when you actually type the line in terminal)
    6. From there, it should launch the installer and you "go from there"

    If you try this, get back to us and let us know how it went...
  5. danielkun thread starter macrumors newbie

    Mar 15, 2014
    Thank you but that did not work. I'm guessing the above "startosinstall" command only works when upgrading an existing Mac OS installation.

    When doing a clean install there are additional steps such as which drive to use.

    That being said, the above startosinstall returns error when executed from the terminal. The full path (from the USB drive) is:

    I did find the GUI installer here:

    Executing this command did start the installer but it also outputs some errors in the terminal window and didn't progress very well so I ended up restarting my Mac mini during the install. I did try to add the " --converttoapfs NO" argument when executing the InstallAssistant but I don't even know if such an argument can be passed.
  6. DeltaMac macrumors G3


    Jul 30, 2003
    In your first post, you said that the Windows install defaulted the boot disk to Windows.
    Why did you not just change the default to macOS in Startup Disk pane, after booting back to your macOS boot system?

    Have you been trying to use the Boot Camp assistant to make the Windows partition and begin the Windows install?
    I have done completely clean installs of HS on my two Macs, both adding Windows 10 using the Boot Camp assistant.
    Neither had any problems with that install, and using APFS on the Mac did not interfere with the Boot Camp install in any way.
    I was careful to use the "Creator's update" ISO for a Windows 10 install, and not a newer "Anniversary" install, which still has problems installing on a boot camp partition, AFAIK.

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5 November 3, 2017