Downgrade from Catalina - bootable drive problem

[Ewan Hails]

Hi guys,

Just purchased a new 16" 2019 MBP, my previous MBP having succumbed to a liquid-related death. I use my MPB mainly for music production and the 64bit limitation on Catalina is causing issues with some older plugins, and also it doesn't seem to be playing nice with the various drivers for USB equipment.

I'm looking to downgrade to Mojave for the time being until I find alternatives to the issues I'm currently having. However I've encountered these problems:

1) Can't download Mojave from App Store to new MBP(I get an "update not found - the requested version of macOS is not available"), from another machine it will download but when I try to open it it says it's broken (expired certificate?)
2) Have found various torrent-downloaded version of Mojave (10.14.6, 10.14.3)
3) Have used the createinstallmedia command to create bootable USB from the various torrent-sourced Mojaves, the command seems to work fine but the USB key isn't recognised as bootable either on the 2019 MBP or a 2012 MBAir. On the 2019 MBP I've made sure to allow booting from an external drive.
4) Have used createinstallmedia with the App Store version of Mojave (the one that won't open cause it says its broken) but it still won't make bootable USB.
5) I've tried the Option-Shift-Command-Period in case the key uses Option ROM.
6) I've tried making bootable drives from 3 machines (2015 MBP, 2012 MBAir, and my new machine)

This is the Mojave version I've been using from App Store: https://apps.apple.com/us/app/id1398502828?ls=1&mt=12

I've tried to many internet searches but can't seem to make anything work. Have been at it for quite a few days on & off now and starting to feeling very frustrated...

HELP!!!

 

[CoastalOR]

The bad news is that the new 16" MBP does not support Mojave.

If you want to boot from an external device (like a USB installer) you have to configure the T2 chip to allow it using the Startup Security Utility app.

About Startup Security Utility on a Mac with the Apple T2 Security Chip - Apple Support

Use Startup Security Utility to make sure that your Mac always starts up from your designated startup disk, and always from a legitimate, trusted operating system.

support.apple.com

About Startup Security Utility on a Mac with the Apple T2 Security Chip – Apple Support (UK)

Use Startup Security Utility to make sure your Mac always starts up from your designated startup disk and always from a legitimate, trusted operating system.

support.apple.com

Mac computers with the Apple T2 Security Chip - Apple Support

Learn which Mac computers have the Apple T2 Security Chip.

support.apple.com

 

[chabig]

As has been said, the 2019 Mac won’t run Mojave. But on top of that, when you want to get installers in the future, don’t get them from arbitrary websites or torrents. Always get the, from Apple. Go to apple.com/support and search for the version name + “installer”.

 

[Fishrrman]

A 16" MacBook Pro REQUIRES Catalina to boot.
It CANNOT boot from Mojave -- no way, no how, not gonna happen.

You COULD install something like Parallels or VMWare fusion (or maybe the free "virtual box"), and install Mojave as a "virtual machine", and run it that way. But not sure how well that will work with DAW stuff, if at all.

So -- you have some hard truths to face:
- You CANNOT run 32 bit software on the 16" MBP -- at least not under the bootable OS.
- You might be able to run 32 bit software under a virtual machine, but the performance aspect remains unknown at this point.

What to do?
- You could update all your software to 64 bit software that WILL run under Catalina.
- If you are in "the return window", you could return the MBP right away for a refund.
- Then... you could look for ANOTHER MAC that will still boot and run under Mojave, and thus run all your software into the near future.

I'd suggest either a well-equipped Mac Mini, or perhaps an iMac.

Personal experience:
I bought a 2018 Mini for the specific reason that I wanted one of the last Macs that WOULD continue to run 32 bit software indefinitely. It came with Mojave and I have no plans to upgrade the OS on it further...

 

[Ewan Hails]

As has been said, the 2019 Mac won’t run Mojave. But on top of that, when you want to get installers in the future, don’t get them from arbitrary websites or torrents. Always get the, from Apple. Go to apple.com/support and search for the version name + “installer”.

As I mentioned in my initial post, I attempted to do this from two different computers, there seems to be an issue with the version that App Store is offering.

A 16" MacBook Pro REQUIRES Catalina to boot.
It CANNOT boot from Mojave -- no way, no how, not gonna happen.

You COULD install something like Parallels or VMWare fusion (or maybe the free "virtual box"), and install Mojave as a "virtual machine", and run it that way. But not sure how well that will work with DAW stuff, if at all.

So -- you have some hard truths to face:
- You CANNOT run 32 bit software on the 16" MBP -- at least not under the bootable OS.
- You might be able to run 32 bit software under a virtual machine, but the performance aspect remains unknown at this point.

What to do?
- You could update all your software to 64 bit software that WILL run under Catalina.
- If you are in "the return window", you could return the MBP right away for a refund.
- Then... you could look for ANOTHER MAC that will still boot and run under Mojave, and thus run all your software into the near future.

I'd suggest either a well-equipped Mac Mini, or perhaps an iMac.

Personal experience:
I bought a 2018 Mini for the specific reason that I wanted one of the last Macs that WOULD continue to run 32 bit software indefinitely. It came with Mojave and I have no plans to upgrade the OS on it further...

Thanks for your feedback.

I'll stick with Catalina on this new machine and figure out some alternatives for the plugins that won't work. It's only a handful of them anyways.