I'm trying to figure out some options for my Mac Mini (latest version of Mojave).
From what I've read, you can boot while holding down command-R Which lets you install the latest INSTALLED version of macOS on your mac (at present, that would be the same thing I have now), but won't upgrade to the latest version. But since I have the latest version already, it would be the same thing. I did this once and, sure enough, it booted differently so I guess that works, but it wasn't what I really wanted to check so I rebooted again.
You can do Opt/Command-R which is supposed to update you to the latest OS compatible with your mac. I didn't try this one, but if it does work, it should do the same as the prior one on my particular mac. If I did it on my iMac which has the prior version of Mojave, I assume it would update to the newest one. I did not test this one.
Which brings me to the problem one. Shift/opt/command-R is supposed to install the version of macOS that came with the Mac. I do not know for sure about the details. From what I've read, if you have a computer than came with High Sierra and then upgraded to Mojave, this would put High Sierra back on it. I do not know if you had an earlier version of Mojave and later upgraded, would this put it back with the older version.
This is what I was trying to test, but it isn't doing what it's supposed co do, based on what I've read.
I've held down those keys and I guess it did something because after booting, I only have one desktop rather than two. But it is supposed to show "macOS utilities" (apparently NOT the same as disk utilities). From there you can choose to "Restore from Time Machine Backup", "Reinstall macOS" (which is what I want), "Get help online", and "disk utility".
Trouble is, I don't see these choices ever come up! Anyone know what I'm doing wrong? Or has Mojave now made it where you can't do this?