Possible to re-format APFS to HFS+?

Discussion in 'macOS' started by macmesser, Jan 16, 2019.

  1. macmesser macrumors 6502a

    Aug 13, 2012
    Long Island, NY USA
    I formatted an SSD destined to become my new High Sierra boot disk as APFS, not realizing that HFS would have been fine. Is there any way I can re-format this drive to HFS+? They ought to issue a warning before formatting a drive as APFS, to the effect that Disk Util can re-format HFS as APFS but not APFS to HFS. Is there any command line way to completely erase APFS format and start clean?
  2. chabig macrumors 603

    Sep 6, 2002
  3. Fishrrman macrumors P6


    Feb 20, 2009
    OP wrote:
    "Is there any command line way to completely erase APFS format and start clean?"

    The problem with doing this is that it's going to DESTROY any data that's already on the drive.
    You may already know this.

    Really, if you have an APFS drive that you want to change to HFS+, the best way to "do it right" is to:
    1. Back up any data on it to another drive. I recommend creating a bootable cloned backup using CarbonCopyCloner.
    2. BOOT FROM the cloned backup drive
    3. Open Disk Utility and ERASE the target drive to Mac OS extended with journaling enabled.
    4. Quit Disk Utility and Open CCC.
    5. Now, RE-CLONE the contents of the cloned backup BACK TO the original drive.
  4. macmesser thread starter macrumors 6502a

    Aug 13, 2012
    Long Island, NY USA
    Thanks for reply. I have been using CCC and that is what I did, except I cloned to the different SSD with which I wish to swap the old one out. The original boot SSD had a verification problem which Disk Utility couldn't fix. The newly cloned system, on a larger SSD which I had reformatted to journaled Mac file system from APFS, did not have the verification problem according to Disk Utility and was bootable at first. I booted and restarted from it several times but it then started refusing to boot, displaying a "stop" symbol (circle with diagonal bar through) which stops the boot process. The drive itself tests good. Any idea what could be going on here? Could the identical systems, original and clone, be getting confused? BTW, when you refer to CCC bootable backup, do you mean an image file or actual volume?

    Maybe I need to do a clean install, in which case I'll try it on the SSD that won't boot.
  5. holty macrumors newbie

    Feb 23, 2007
    Townsville Australia

    Is this same process applicable to the OEM SSD inside my Late 2015 27inch iMac which was "auto converted" upon installing 10.14.0
  6. gilby101 macrumors regular

    Mar 17, 2010
    Do you have a reason for wanting to use HFS+. APFS is much better particularly for SSDs.
  7. zorinlynx macrumors 603


    May 31, 2007
    Florida, USA
    APFS has proven itself as a reliable filesystem. Hundreds of millions of iOS devices are using it, and millions of Macs too. The only reason you would want to use HFS+ is compatibility with older MacOS versions, and Linux and other operating systems.

    Just saying, this may be a pointless quest. :)

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6 January 16, 2019