Creating A Bootable External Hard Disk With Mac OS High Sierra On A Macbook Pro With Catalina

[siennathesky]

Hey guys,

I'd greatly appreciate any help i can get with this.

I just bought a macbook pro 2019 with mac os catalina on it. I also got a samsung T7 the other day. I'm hoping to use the T7 as a bootable hard disk with high sierra on it.

I tried two things -

1) tried downloading high sierra from the app store after visiting this link - https://support.apple.com/en-us/HT211683, but got the message the following message -
'Update not found.
The requested version of macOS is not available.'


2. downloaded a .dmg of high sierra 10.12 off this page - https://support.apple.com/kb/DL1946?viewlocale=en_US&locale=en_US, I open the .pkg file but get a message saying 'This software is not support on your system'.


3. downloaded an iso of high sierra off a website (not sure which one). This is the message i get when open the file and try to install it -
' “Install macOS High Sierra” cannot be opened because the developer cannot be verified. '

Please help me.

 

[Mike Boreham]

I don't believe any 2019 model of MBP will run High Sierra, it is too old. According to MacTracker, it looks like Mojave 10.14.5 is the oldest. But 16" 2019 MBPs need Catalina 10.15.1 or later.

Any special reason for High Sierra? Mojave will run 32 bit apps if that is the reason.

 

[siennathesky]

Nope, no particular reason. I have the 16", guess i can't do **** now.
But atleast now I know. Thanks a ton Mike!

 

[deeddawg]

Can't run any macOS version older than what was current when the model was created.

If you need to run High Sierra for something, you'll need to get a 2017 or earlier model to run it on.

 

[David Hassholehoff]

Or you could run it in VMware. I did this for awhile when Catalina dropped 32-bit support.