Downgrade from macOS Mojave to High Sierra.

[lukemcfc]

Hey,

 

Does anyone know how to downgrade from Mojave to High Sierra or Sierra (I have Install macOS Sierra.app) without the use of a Flash Drive.

[Hashiba]

Hi @lukemcfc,

 

I don't think that is possible there a lot of changes that happened at system level form High Sierra to Sierra, and Mojave has a totally different metal/openCL integration, So even If could manually mix and match some of the kexts it would be almost impossible.

 

My suggestion is that you copy your important data to an external drive and reinstall High Sierra, preferably from a usb 3 drive

 

you could also try a remote install, but I believe that once Mojave is in your drive, the remote install won't give you the option of installing another version, such as HS.

 

High Sierra is still available on the store so you should not have any problems building a new usb installer

 

[Tabs]

55 minutes ago, lukemcfc said:

Hey,

 

Does anyone know how to downgrade from Mojave to High Sierra or Sierra (I have Install macOS Sierra.app) without the use of a Flash Drive.

What mac do you have mate?

 

An internet recovery can reinstall the version of MacOS your machine came with.

 

I downgraded from Mojave to Sierra on my 2016 MacBook pro using this method, and ever since it got replaced by a 2017 MacBook pro, it now downgrades to High Sierra instead the same way. This does not need a USB flash drive, only access to the internet.

 

Depending on your specific model of mac, you'll want to either boot while holding shift-command-R or shift-option-command-R.

 

The differences and documentation is available here: https://support.apple.com/en-gb/HT204904

[lukemcfc]

On 7/16/2018 at 1:12 PM, Tabs said:

What mac do you have mate?

 

An internet recovery can reinstall the version of MacOS your machine came with.

 

I downgraded from Mojave to Sierra on my 2016 MacBook pro using this method, and ever since it got replaced by a 2017 MacBook pro, it now downgrades to High Sierra instead the same way. This does not need a USB flash drive, only access to the internet.

 

Depending on your specific model of mac, you'll want to either boot while holding shift-command-R or shift-option-command-R.

 

The differences and documentation is available here: https://support.apple.com/en-gb/HT204904

Its a 2012 MacBook Pro. Thanks for the help!

[lukemcfc]

On 7/16/2018 at 12:21 PM, Hashiba said:

Hi @lukemcfc,

 

I don't think that is possible there a lot of changes that happened at system level form High Sierra to Sierra, and Mojave has a totally different metal/openCL integration, So even If could manually mix and match some of the kexts it would be almost impossible.

 

My suggestion is that you copy your important data to an external drive and reinstall High Sierra, preferably from a usb 3 drive

 

you could also try a remote install, but I believe that once Mojave is in your drive, the remote install won't give you the option of installing another version, such as HS.

 

High Sierra is still available on the store so you should not have any problems building a new usb installer

 

Okay thanks!