Chosen Solution
I successfully replaced the failed drive in my dual drive Mac Mini Server with a 960 GB Toshiba SSD - thank you iFixIt! However, the failed drive was the original boot drive and I am getting an error message when I try to log in to the server to format the new hard drive (which I planned to do via Time Capsule or Super Duper). I am able to access files and the second hard drive is functioning ok as the server but I am not getting use of the new hard drive that I can then duplicate on the second hard drive for backup purposes. Any ideas???
The easiest way here is to create a USB thumb drive installer. Follow this guide: How to create a bootable macOS Sierra installer drive As much as you want the very latest MacOS I caution you not to! High Sierra alters the GUID/Mac OS Extended (Journaled) volume to APFS when it sees a SSD. The issue here is the fact your system is SATA based SSD not a PCIe based SSD so it messes up the drive as the thinks it has the deeper number queues a PCIe has when in fact it doesn’t! This makes coping & saving files within finder very slow! OK so we’ll stick with Sierra for now until Apple comes up with an update to address the queuing issue for High Sierra. Now with the thumb drive boot up holding the Tab key to gain access to the boot manager, select the USB thumb drive and then run Disk Utility to setup the GUID/Mac OS Extended (Journaled) volume. Once don run the installer (just make sure you’ve selected the correct drive) That should do it!
