Install High Sierra on MacBook Pro 2012

ANARGET wrote:

My MacBook Pro (13-inch, Mid 2012) has Catalina and Mojave installed on separate AFPS volumes. I want to install High Sierra as well. I have created a High Sierra volume and downloaded High Sierra from the App Store. I then created a bootable High Sierra USB. Can anybody explain how I proceed and install to the High Sierra volume please.

https://support.apple.com/guide/disk-utility/add-erase-or-delete-apfs-volumes-dskua9e6a110/mac

Hi Anarget,

Great job so far! The last step to install macOS High Sierra is to start up from the bootable installer you made.

NOTE: These steps will only work if your MacBook Pro has a solid state drive (SSD) inside. If it has a rotational hard drive (HDD), you'll need to first delete the High Sierra APFS volume and create a new Mac OS Extended (Journaled) partition instead. This is because macOS High Sierra only uses APFS on SSDs.

1. Connect the bootable installer to your Mac.
2. Restart your Mac while holding down the Option key. Release the key when a selection of startup disks appear.
3. Use the arrow keys to select "Install macOS High Sierra", then hit Enter (Return).
4. Select Install macOS from the Utilities window, then follow the onscreen instructions to install macOS High Sierra.

I’d blame the bad performance on APFS then. APFS is optimized for SSDs, and has features that perform rather poorly on rotational hard drives (such as copy on write).

Mac OS Extended (Journaled) is optimized for hard drives - it stores all of the volume and file metadata at a known location on disk. This is in stark contrast to APFS, which stores file metadata next to the associated file - causing many unnecessary seeks on HDDs, but no performance impact on SSDs.

EDIT: Blame the hard drive as well; SSDs are blazing fast these days.

Thanks! 👍