I have a 2018 Intel Based i7 Mac Mini, and it was a zero day exploit so it downloaded a 400 MB approx update.
I loaded it Friday 09/08/2023 morning and when it rebooted it halts about half way with the Apple logo and won’t fully boot to the login screen. I cannot even get to the login screen.
I have made bootable USB installers of Ventura 13.5.2 and I have reinstalled MacOS numerous times with the same result.
Today, I am trying to install MacOS to a Thumb Drive, with the hopes of booting up into MacOS Ventura 13.5.2 so that I can use Carbon Cloner to copy my internal disk to another NVME external drive so that I can boot off of it and then restore it back to the internal disk and boot off of it and use it again.
However, upon installation to the USB 256GB SanDisk, I got a continuous reboot when it tries to boot up now.
The good news is that I don’t believe that our hardware is damaged. I think there is a flaw with this update.
My proof is that prior to upgrading to Ventura, I used Carbon Cloner to make a bootable external image using a USB 1TB HDD of Monterey. Yes it boots up perfectly, but slow. But shortly after booting up I hear the clicking sounds of potential disk failure. It’s a 7200 RPM HDD.
So I have to figure out another strategy. Or wait for 13.5.X to come out so that I can make another bootable USB to upgrade my way out of this mess.
I am currently trying to install it to an external USB C Thunderbolt device a Sabrent Tech NVME drive with a 1TB WD NVME SSD.
If it does the same thing, I will report back here.
It’s sad, because I felt compelled to load the Security Patch, and instead it made my system unusable. I am sure that was not the intended result.
I honestly don’t like how they kind of lock you out from downgrading, without reformatting the whole disk. But I am sure that they have their reasons.
From now on, I will always back up before I do a small update using Carbon Cloner with an NVME drive. Yes they can fail like a HDD can, and yes they are more expensive, but when you need a solid working backup, I don’t need to her HDD failure clicks from my only backup…
I am confident that the folks at Apple will get it fixed, and we will be able to make a new bootable USB installer and we will be back up and running again.
The upside is that I learned a heck of a few new things that I didn’t know before, and I chalk this up to a positive learning experience, even though I currently cannot use my system. It thankfully I have others until they can get this fixed.
Now, sometimes memory modules can go bad. So that could be a problem also. But if you can boot and use a prior backup of MacOS Monterey like I did, it means that it is probably not the Hardware that is the problem.
Especially when I am getting similar results like you are where it keeps rebooting. Although mine is doing it at startup.