I am using the Install macOS Mojave.app installer on my Mac mini (2018) running Mojave 10.14.5 to install Mojave on a formatted external spinning disk laptop drive (a Toshiba model with case).

I successfully formatted the drive using Disk Utility app in the GUID format.

Now when running the Mojave installer, it refuses to install on the external drive saying:

This Mac can only install macOS on APFS-formatted drives.

But I thought APFS was intended only for solid-state drives, not spinning drives. And there was no APFS option in Disk Utility that I could see.

➥ Is it now impossible to install and boot on an external spinning drive?

1 Answer 1


You are almost there. Check again in Disk Utility app.


You will find APFS as an option in the Format pop-up menu.


You make the same choice of GUID Partition in the other pop-up menu Scheme.

screenshot of Disk Utility > Erase > Format > APFS.

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