As a follow-up to my
installation of a DIY Fusion Drive on the 2011 Mac mini, there are some clarifications that have become useful a few years later on. I wanted to reformat the drives with a fresh operating system to pass along the computer to a family member, but was getting errors during installation.
The bottom line is that the install process does not work on a freshly-created Fusion Drive, but you can get around this by restoring a Time Machine backup onto the new Fusion Drive. Along the way, I discovered how to make a DIY Fusion Drive with a properly working recovery partition for troubleshooting in the future. The 2011 Mac mini only supports up to macOS High Sierra, though I suspect this is all resolved in Mojave/Catalina thanks to the luxuriously simple "
diskutil resetFusion" command that I was able to use on a 2014 machine.
The issue is that the macOS High Sierra installer will give errors when doing a clean installation on a DIY Fusion Drive system, reporting either “macOS could not be installed on your system - invalid request” or “the installer resources were not found”. I got nervous because I was already in Recovery mode and a fresh install was failing... was the computer just toast now?!?
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First comes the "invalid request" error |
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And if you reboot, you get "the installer resources were not found" |
It turns out that the solution is to split the drives up, do a regular install onto the hard drive, use that to create a Time Machine backup, then rebuild the Fusion drive, and restore the backup (i.e. NOT a new install). Phew! (Thanks to
this thread for pointing me in the right direction.) OK let’s do this in detail: