Need help installing Mojave on 2019 MBP

[darkmatter343]

Got a new MBP 2019 13” Delivered this week, which came with Catalina installed naturally, however I need 32bit support. I downloaded the Mojave install, the full install over 6gb and made the USB key ok. First issue came when I went to boot off it, since Apple now locks down Secure Boot, I had to first boot into the Catalina Recovery and disabled it. I choose the middle or medium security option.

But, here’s where the issue starts. I booted off the USB key, but immediate get a message that there is something wrong with the installer on the key. Ok, no problem. Reboot into OSX, and remake it again, this time using Apple’s own instructions. Reboot, same issue. Arg...
So after some reading that suggested it could be due to Catalina’s APFS partition, I booted back into the Catalina Recovery and deleted all the main HD partitions. I made sure to show hidden devices so that the top root level HD was completely wiped. Alright, now lets try booting off that Mojave USB Key again...

Nope... What’s going on?

So now Whenever I try to boot from the Mojave USB with the Option Key, I choose the Mojave installer, although I have to connect to WiFi and it starts the Internet Recovery. When it finally loads, I still get the same error “The version of macOS on the selected disk needs to be re-installed” so frustrating. I really need to downgrade to Mojave,

Thanks in advance for any and all help/suggestions!

 

[Audit13]

A 2019 MacBook can't run an OS that is older than the OS it came with AFAIK.

 

[chscag]

A 2019 13" MacBook Pro should be able to run Mojave. Only the 16" 2019 MacBook Pro can not run Mojave. Unless Apple updated or did something to the firmware, he should be able to install Mojave.

 

[Audit13]

A 2019 13" MacBook Pro should be able to run Mojave. Only the 16" 2019 MacBook Pro can not run Mojave. Unless Apple updated or did something to the firmware, he should be able to install Mojave.

I incorrectly assumed it was because the MacBook shipped with Catalina.

Since the MacBook shipped with Catalina, I assume internet recovery will install Catalina too.

 

[Fishrrman]

WARNING:
Doing the following will WIPE OUT any data on the internal drive.
So... back it up before proceeding.

I would suggest you try this:
1. Boot to a special version of internet recovery:
Shift-Option-Command-R

This should enable you to re-install the version of the OS that ORIGINALLY SHIPPED with the 2019 MBP (which should be a version of Mojave).

You'll need your wifi password and it will take a while to load up, so be patient.

2. When you get to the utilities menu, open disk utility.

3. In disk utility, go to the view menu and choose "show all devices" (VERY important that you do this step)

4. Now, on the left, click on the topmost line that represents the physical drive inside the MBP

5. ERASE it to APFS with GUID partition format.

6. Quit disk utility and open the OS installer, and begin clicking through.

7. Install the OS. When done, begin clicking through.

8. If you are going to restore from a backup, connect it when the setup assistant asks if you wish to migrate from another drive.

If not, just create a new account when prompted.

 

[chrfr]

Got a new MBP 2019 13” Delivered this week, which came with Catalina installed naturally, however I need 32bit support. I downloaded the Mojave install, the full install over 6gb and made the USB key ok.

Do you have a 10.14.6 installer and did you recently download it directly from Apple? If it's an older installer (even if it's 10.14.6), the problem may be that the certificate used to sign the installer has expired.

 

[4sallypat]

Instead of dealing with the shortcomings of the recovery partition, I have a selection of many different OS on USB bootable drives which I pick and choose which version I want.
But the newer units can't go to an older OS than what it originally came with...

 

[Audit13]

Instead of dealing with the shortcomings of the recovery partition, I have a selection of many different OS on USB bootable drives which I pick and choose which version I want.
But the newer units can't go to an older OS than what it originally came with...

This is what I also thought but someone else said this is not correct?

 

[darkmatter343]

Thanks for all the replies, got it solved! I ended up putting Catalina back on temporarily, since I wiped the Macbook, but then I immediately booted back into the Recovery and changed the Startup Security to the lowest setting. (Originally I had changed it to medium)

After doing that, I booted off the same USB Mojave key that previously prompted with the error I posted above, and voila! I could now install Mojave! PITA process, but it worked

I get Why Apple abandoned 32bit support, at some point it had to happen, but it sure left a lot of apps in the dust.

 

[chscag]

Great, glad to hear you resolved it. Your particular MBP as we stated above, could install Mojave. Only the 16" 2019 model is excluded and can only run Catalina.

 

[darkmatter343]

Great, glad to hear you resolved it. Your particular MBP as we stated above, could install Mojave. Only the 16" 2019 model is excluded and can only run Catalina.

Yeah, it was the 2019 MBP (base 256GB) or the new MBA 2020 with the i5 and 512GB, which I wanted for it’s magic keyboard and QC. I much prefer the sloped palmrest on the airs, and besides I don’t need the power of the MBP, however I DO need 32bit app support. Oh well.