Mac Mini 2018 roll back catalina

[troop5150]

Hello all.
Recently purchased a mac mini 2018. I was using hdmi to a Dell monitor and everything was displaying and working fine. However after updating to Catalina all I get is a black screen after the initial loading screen on both monitors. I tried purchasing both usb c to hdmi and usb c to displayport cables and neither work on either one of the monitors. I know there is nothing wrong with the Mac Mini itself as I can get all cables to work fine with my living room TV.
All I want to do now is roll back to a previous version of Catalina or Mojave. I tried to do so using internet recovery but I get error -1008f every time be it by wifi or ethernet cable. I also lowered my security settings and allowed boot via usb, but the mac mini doesn't display the usb as option on boot. The only recovery option that seems to be possible is re installing the current version of Catalina, which would be pointless in my case.
I'm open to any suggestions. I just want to go back to an earlier version of Catalina or back to factory installed os.

Thank you

 

[Fishrrman]

OK, I'll help.
This is going to take a number of steps.

FIRST:
MAKE SURE YOU ARE BACKED UP, because your internal drive is going to be "wiped out". I recommend an external USB3 drive and either CarbonCopyCloner or SuperDuper (both are FREE to download and use for 30 days).

Next:
DISCONNECT the second monitor and set it aside.
DO NOT attempt to re-connect it until later on.
You want only a single monitor that works.
DISCONNECT all peripherals you have connected except for the keyboard and mouse.

Now:
Boot to the follow SPECIAL VERSION of "internet recovery":
shift option command R
If you are using wifi to connect, you'll need your wifi password.
This is supposed to restore you to the version of the OS that originally shipped with your Mac (in your case, it should be Mojave).

Then:
Wait for the utilities to load (can take a while).
Open disk utility.
IMPORTANT IMPORTANT IMPORTANT:
Go to the "view" menu and choose "show all devices".

Next:
On the left, choose "the top line" in the list that represents the physical drive inside the Mini.
ERASE IT to APFS with GUID partition format.

Now:
Close disk utility and open the OS installer
See if it will install a fresh copy of Mojave to the empty drive.
This will involve a few reboots, a few "dead moments", and several progress bars.

Then:
If this works, you'll see the setup screen "choose your language".
Begin "clicking through" the setup.
When setup assistant asks if you wish to migrate data from another drive, you can TRY connecting the external backup.
BE AWARE that setup assistant MAY NOT be agreeable to "migrating" data from a backup that was created by a newer version of the OS, but give this a try anyway.
IF IT DOESN'T WORK, there are "other ways" to "get at" the data. But don't worry about that now.

Does this work?
Can you get up-and-running with Mojave this way?

If it works, try connecting the second display again.
Any better?

If this works, THE BEST ADVICE I CAN GIVE:
NEVER try to install Catalina again.
Be happy with Mojave for now.
Wait until September when Mac OS 10.16 is introduced.
When it's released, EXPERIMENT with that by installing it on AN EXTERNAL DRIVE before you attempt to "upgrade".

PRINT THIS OUT and check off each line as you go along!

 

[troop5150]

OK, I'll help.
This is going to take a number of steps.

FIRST:
MAKE SURE YOU ARE BACKED UP, because your internal drive is going to be "wiped out". I recommend an external USB3 drive and either CarbonCopyCloner or SuperDuper (both are FREE to download and use for 30 days).

Next:
DISCONNECT the second monitor and set it aside.
DO NOT attempt to re-connect it until later on.
You want only a single monitor that works.
DISCONNECT all peripherals you have connected except for the keyboard and mouse.

Now:
Boot to the follow SPECIAL VERSION of "internet recovery":
shift option command R
If you are using wifi to connect, you'll need your wifi password.
This is supposed to restore you to the version of the OS that originally shipped with your Mac (in your case, it should be Mojave).

Then:
Wait for the utilities to load (can take a while).
Open disk utility.
IMPORTANT IMPORTANT IMPORTANT:
Go to the "view" menu and choose "show all devices".

Next:
On the left, choose "the top line" in the list that represents the physical drive inside the Mini.
ERASE IT to APFS with GUID partition format.

Now:
Close disk utility and open the OS installer
See if it will install a fresh copy of Mojave to the empty drive.
This will involve a few reboots, a few "dead moments", and several progress bars.

Then:
If this works, you'll see the setup screen "choose your language".
Begin "clicking through" the setup.
When setup assistant asks if you wish to migrate data from another drive, you can TRY connecting the external backup.
BE AWARE that setup assistant MAY NOT be agreeable to "migrating" data from a backup that was created by a newer version of the OS, but give this a try anyway.
IF IT DOESN'T WORK, there are "other ways" to "get at" the data. But don't worry about that now.

Does this work?
Can you get up-and-running with Mojave this way?

If it works, try connecting the second display again.
Any better?

If this works, THE BEST ADVICE I CAN GIVE:
NEVER try to install Catalina again.
Be happy with Mojave for now.
Wait until September when Mac OS 10.16 is introduced.
When it's released, EXPERIMENT with that by installing it on AN EXTERNAL DRIVE before you attempt to "upgrade".

PRINT THIS OUT and check off each line as you go along!

Thanks for the response. I was not able to use the special internet recovery successfully. I was however able to create Mojave usb boot drive using a mac book. I wiped the disk and installed mojave on the mac mini. Unfortunately the version of mojave i downloaded via the app store was the last version 10.4.6 and is not the version that came with the mac mini I assume because the monitors still only display the loading screen and then go black.

I returned the mac mini to Micro Center and exchanged it for another of the same model. This one is the same out the box It works with my living room tv but not with my monitors.

I purchased a belkin usb c- hdmi adapter that was recommended via reddit. After purchasing the usb-c to hdmi and usb c to displayport cables I was a bit apprehensive to purchasing something else but I'm kind of out of options besides returning it and getting my money back. I really hope the adapter works but it doesn't arrive for about 10 days.

So I decided to google "how to create a bootable usb from a DMG" and I only found guides on how to do so from a Windows PC but they seem to be pretty outdated. I want to create a bootable usb of Mojave 10.4.2 or anything before 10.4.6. I am able to download the DMG from the apple downloads page but I do not know how to create a bootable USB from it. If there is any guides available online I would appreciate the link. Or if there is a better search term for what I'm trying to do I would appreciate that as well. Lol.

Thank you

 

[chrfr]

So I decided to google "how to create a bootable usb from a DMG" and I only found guides on how to do so from a Windows PC but they seem to be pretty outdated. I want to create a bootable usb of Mojave 10.4.2 or anything before 10.4.6. I am able to download the DMG from the apple downloads page but I do not know how to create a bootable USB from it. If there is any guides available online I would appreciate the link. Or if there is a better search term for what I'm trying to do I would appreciate that as well. Lol.

Thank you

Apple doesn't make full installers available for anything but 10.14.6. What you've found on the Apple downloads page are updaters that require you starting with 10.14 already being installed.

 

[Rolomoto]

All the Mojave versions on apple downloads say update, is there any way to get a full version?
I want to create a Movaje USB installer and get rid of Catalina. I have a 2012 mini and internet recovery will install Mavericks.
thanks

 

[CoastalOR]

All the Mojave versions on apple downloads say update, is there any way to get a full version?
I want to create a Movaje USB installer and get rid of Catalina. I have a 2012 mini and internet recovery will install Mavericks.
thanks

Here are the Apple Instructions with a link to the App Store to get the Mojave full installer:

How to download and install macOS - Apple Support

Download and install current or previous versions of the Mac operating system on compatible Mac computers.

support.apple.com

The App Store may not let you download Mojave if you use a Mac with a newer OS (Catelina). You will probably need a Mac capable of running Mojave that does not already have Catalina installed.

 

[newellj]

OK, I'll help.
This is going to take a number of steps.

FIRST:
MAKE SURE YOU ARE BACKED UP, because your internal drive is going to be "wiped out". I recommend an external USB3 drive and either CarbonCopyCloner or SuperDuper (both are FREE to download and use for 30 days).

Next:
DISCONNECT the second monitor and set it aside.
DO NOT attempt to re-connect it until later on.
You want only a single monitor that works.
DISCONNECT all peripherals you have connected except for the keyboard and mouse.

Now:
Boot to the follow SPECIAL VERSION of "internet recovery":
shift option command R
If you are using wifi to connect, you'll need your wifi password.
This is supposed to restore you to the version of the OS that originally shipped with your Mac (in your case, it should be Mojave).

Then:
Wait for the utilities to load (can take a while).
Open disk utility.
IMPORTANT IMPORTANT IMPORTANT:
Go to the "view" menu and choose "show all devices".

Next:
On the left, choose "the top line" in the list that represents the physical drive inside the Mini.
ERASE IT to APFS with GUID partition format.

Now:
Close disk utility and open the OS installer
See if it will install a fresh copy of Mojave to the empty drive.
This will involve a few reboots, a few "dead moments", and several progress bars.

Then:
If this works, you'll see the setup screen "choose your language".
Begin "clicking through" the setup.
When setup assistant asks if you wish to migrate data from another drive, you can TRY connecting the external backup.
BE AWARE that setup assistant MAY NOT be agreeable to "migrating" data from a backup that was created by a newer version of the OS, but give this a try anyway.
IF IT DOESN'T WORK, there are "other ways" to "get at" the data. But don't worry about that now.

Does this work?
Can you get up-and-running with Mojave this way?

If it works, try connecting the second display again.
Any better?

If this works, THE BEST ADVICE I CAN GIVE:
NEVER try to install Catalina again.
Be happy with Mojave for now.
Wait until September when Mac OS 10.16 is introduced.
When it's released, EXPERIMENT with that by installing it on AN EXTERNAL DRIVE before you attempt to "upgrade".

PRINT THIS OUT and check off each line as you go along!

Quoted to say thanks for this. Looking at updating my Mini to a 2018 model and I need it to run Mojave.

 

[Hessel89]

I was not able to use the special internet recovery successfully.

Just curious, did you also get this message a few minutes after pressing shift + option + command + R?

Also, when you've successfully updated to Mojave, don't install the 10.14.6 supplemental update. It's awful. It causes your Mac mini to crash while sleeping. It's related to the T2 chip. It panics when waking up from sleep for some reason.

 

[newellj]

Just bought one of the 2018 refurbs. Hopefully this works; if not I have the installer. Should be GTG either way. Thanks again!