Could not create a preboot volume for APFS install error while installing on Squid RAID

Discussion in 'Mac Pro' started by matthewpomar, Apr 28, 2019.

  1. matthewpomar, Apr 28, 2019
    Last edited: Apr 28, 2019

    matthewpomar macrumors member

    Oct 27, 2010
    I have upgraded my 2009 Mac Pro to macOS Mojave with a 141 boot ROM.

    I have a Squid with 4 x 512 NVMe Samsung Pro 970s, setup as RAID 0 and formatted APFS.

    My primary boot drive is a Kingston HyperX Predator AHCI drive.

    I'm trying to install macOS Mojave onto the Squid RAID drive and migrate everything over to that. However, when I run the installer and choose the Squid RAID volume, it starts the installation but then I get the following error:

    > Could not create a preboot volume for APFS

    Since posting this, I've been reading that macOS Mojave will not boot from a RAID volume via any supported configuration. Does anyone know if this is still true with the latest boot ROMs?

    Any one know what I need to do to get past this problem?
  2. chrfr macrumors 604

    Jul 11, 2009
    There's no change to the lack of RAID boot support with APFS/Mojave. You'll need to use the array as a secondary disk.
  3. REYNE, May 1, 2019
    Last edited: Jun 7, 2019

    REYNE macrumors newbie

    May 1, 2008
    Yes, I have the same SQUID setup and it is somewhat painful.

    I am using the boot ROM - - which works fine.

    My method is to install Mojave on a separate internal drive, be it HFS or APFS matters not IME.

    I then clone it to the SQUIDS which are setup using Apple RAID in HFS.

    When there are any updates, I update the separate drive first (which I keep as a system backup), boot to test all working well, then Carbon Copy Clone it back to the SQUIDS.

    APFS is at best immature and plagued with bugs IMO, this RAID issue being a classic example.

    Sure, this is not ideal and the SQUIDS could be running much faster with a previous OS or SoftRAID for example.

    I'm still at 10.13.6 BTW.
  4. matthewpomar, Jun 7, 2019
    Last edited: Jun 7, 2019

    matthewpomar thread starter macrumors member

    Oct 27, 2010
    A few follow-up questions:

    Using the Squid, can I:

    1. Install macOS Mojave on 1 of 4 NVMe blades, then RAID 0 the other 3 for additional storage?

    2. Does the latest macOS 10.14.5 and boot ROM allow us to install on RAID 0?

    3. Could I still install High Sierra on an NVMe RAID 0 with HFS?

    Thank you.
  5. crjackson2134 macrumors 601


    Mar 6, 2013
    Charlotte, NC
    It has nothing to do with the BootROM. APFS simply does not support this configuration.
  6. zedex macrumors member


    Oct 21, 2018
    Perth, WA
    The answer to question 3.. yes - you can still create the RAID0 boot volume under HIGH SIERRA as long as you preserve the HFS+ file system. I do this with the highpoint squid (ssd7101).
  7. jscipione macrumors regular


    Mar 27, 2017
    You can install Mojave on an APFS RAID 0 but it is not supported and the installer has no idea how to make the drive bootable. See the following thread for instructions:

    The trick is to move the mv /usr/standalone/bootcaches.plist out of the way with SIP disabled.

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