2012 Mac mini Fusion drive and fresh install (macOS Catalina 10.15.3)

[Jim Lahey]

Hello folks. I wonder if any of you may be able to reassure me with this.

As a network connected data driving workhorse for shuffling heavy files to and from a NAS and local USB discs, I'm using a Mac mini (late 2012) with a 1TB Fusion drive. It normally handles this task fine. However, I'm recently encountering stability issues and general software hiccups that I do not believe to be hardware performance related. This is slowly leading me to the conclusion that a complete erase/reinstall from a bootable USB may be a good idea. It's never had a clean wipe, so the OS is a legacy from 2012 and pre-APFS.

My question to you all is; am I likely to encounter issues with the partitioning/joining structure of the Fusion drive/s and APFS? Rather, will the system/installer correctly recognise and configure the drive structure accordingly? The last thing I want is a bricked machine with an unusable boot drive. Apple are usually pretty smart with this kind of stuff so I'm hoping all will be well but, as they say, failure to prepare is preparing to fail. Anything I need to know/do/avid doing? Which drive will need to be used when selecting one of the two etc?

Thanks for reading. Hoping for some feedback

EDIT: So, not the best start. Since I am already running 10.15.3 it seems that Apple doesn't want to let me download the installer. I'm currently looking at this guide, which instructs the reader to download the installer, but I cannot seem to do this. "Get" just opens system preferences and checks for updates. Direct links just point me to the App Store again. I don't really want to have to download from a 3rd party source

 

[Fishrrman]

1. BACK UP the internal drive (or whatever drive from which you're currently booting).

2. Boot to INTERNET RECOVERY (NOT to "the recovery partition"):
Command-OPTION-R
You should see "the spinning globe".
If you're connected via wifi you may need your wifi password.
It will take some time to load -- BE PATIENT.

3. Open Disk Utility, go to the view menu, and choose "show all devices".

4. Pick the TOP item on the left that represents your physical internal drive

5. ERASE IT to APFS, GUID partition format.

6. Quit Disk Utility and open the OS installer

7. Install a new copy of the OS. It will take one or more reboots and will take some time. BE PATIENT.

8. When done, begin clicking through setup. When setup assistant asks if you wish to migrate data, "point it" at the backup drive. Select what you want and "let 'er go".

 

[Jim Lahey]

Thanks so much for your reply @Fishrrman. I have have since concluded, after further reading, that your method is the way to go for me. I'm currently in the process of backing up critical data

 

[Jim Lahey]

In the interest of thread completion, besides some not entirely unexpected issues with the Fusion configuration, this eventually all went well and the machine is now working optimally. Or as optimally as you'd realistically expect for a computer of 2012 vintage with only 4GB of RAM. I may boost that up to 8GB just to give it a little more headroom, but that's another conversation. The important thing is that the old girl has some life left in her yet. I still have my MacBook Pro for the fancier stuff anyway.

Thanks again for the help and interest. Much obliged.