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looking for high Sierra install that is compatible with 2018 MacBook Pro  



Hi Folks,

I would like to have the ability to create a second bootable partition on my  2018 MacBook Pro that came pre installed with Mojave. The second partition would be running high Sierra. I had this working perfectly on my old machine (a 2015 MacBook Pro).  

It turns out CCC clones made on older machines won't boot on the newer machines (Mojave and high Sierra), even with the new T2 security features disabled via recovery mode.  This kind of makes sense, because the old bootable versions are going on new hardware, and there may be additional drivers , etc needed.

Also it appears that the bootable High Sierra install that I made previously on my MacBook Pro 2015 , can not be used on this machine, It boots, but fails to install with error message something like "operating system needs to be updated, before  blah blah"

I think it is for the same reasons, that it won't work.

After researching this further, it appears that I need a version of the bootable installer that is compatible with this particular machine, so it has the new drivers for the new hardware. This seems to makes sense. 

However, on the new App Store under Mojave, apple is now making it terribly difficult to download old os's.

Has anyone else run into this and come up with a workaround? I suspect it is finding the correct "Install High Sierra"  build that can be flashed onto an external stick.

Anyone solve this one?


3 Answers

If you have not previously downloaded a macOS version generally you cannot download it at all when there is a newer version that will work on your system.


The exceptions being Lion and Mountain Lion which you paid upgrades, and El Captain which is needed to upgrade from macOS versions older than El Cap to versions newer.


The moral of the story is to ALWAYS download one copy of every new major macOS release, and then it will be in your App Store -> Purchases tab.

This post was modified 2 years ago by datafornothinandbitsforfree

I don’t think it will be in your purchased tab under Mojave. Totally new App Store layout. So I’d suggest downloading all you old os’s from high Sierra or earlier os. 

I did download high Sierra and created a bootable usb  from my 2015 mbp. 

But don’t count on your download to work on a new machine, the software has various branches that need to support the specific hardware you are using it seems. 

I know others have had High Sierra running on the 2018 mbp, so I’m pretty sure there is a compatible install image somewhere. Perhaps at the Genius Bar. 



The Genius Bar is sometimes an option, assuming they are willing, and you have a good reason why you need an older macOS version (for example, 3rd party software compatibility).