Home > Apple File System, Mac administration, macOS > Using the macOS High Sierra OS installer’s startosinstall tool to avoid APFS conversion

Using the macOS High Sierra OS installer’s startosinstall tool to avoid APFS conversion

As part of the upgrade process to macOS High Sierra, Apple has stated that certain drives will be converted from using the HFS+ filesystem to Apple’s new default filesystem, APFS. The conversion criteria is shown below:

Screen shot 2017 09 07 at 5 00 58 pm

For those Mac admins who don’t necessarily want to convert yet, there is a way to configure the macOS High Sierra OS installer to skip the APFS conversion. For more details, please see below the jump.

Apple includes a command line tool named startosinstall as part of the macOS High Sierra OS installer application, inside Install macOS High Sierra.app/Contents/Resources.

Screen Shot 2017 09 26 at 1 19 31 PM

This tool has several options, including a –converttoapfs option which allows control over the APFS conversion process.

To run an automated upgrade to macOS High Sierra, where the APFS conversion is skipped, please run the command shown below with root privileges:

/Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/startosinstall --applicationpath /Applications/Install\ macOS\ High\ Sierra.app --agreetolicense --converttoapfs NO --nointeraction

Note: The –nointeraction flag is an undocumented option to automate the installation process from the command line without additional requiring actions by the logged-in user.

To show what the process looks like when upgrading from macOS Sierra, please see below for a video.

Note: This video has been edited to artificially reduce the amount of time the upgrade process takes to run. Run time of the pre-edited video was 19 minutes 38 seconds.

  1. Mark
    September 30, 2017 at 4:21 pm

    Wish I’d seen this post earlier in the week … would have saved me untold grief. Will keep an eye on your site from now on!

  2. Paulo
    September 30, 2017 at 7:39 pm

    There is some way to skip the firmware check in the installation process??? My installation fails at that point.

  3. Nigel
    October 6, 2017 at 6:21 pm

    Nice work – to “undo” this you would change ‘converttoapfs NO’ to a YES? – or – just install HS as is?

  4. Keram
    October 19, 2017 at 9:00 am

    I would prefer a installation with APFS case sensitiv. How I can do this??

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