
Select your USB drive as the boot device to load the installer. Reboot your Mac and press and hold the Option key while it boots.

We have the partition ready as well as the bootable USB drive. Now starts the last step and most important step.Entering 70 GB would mean that your Sierra partition would be resized to 70 GB and the rest will be reserved for your High Sierra installation. You now have to enter the size of the new partition. Resize the new partition with this file format: macOS Extended (Journaled). Open Disk Utility, select your drive and click Partition. After your bootable USB is created, we will re-partition the disk in your Mac to make space for High Sierra.Open Terminal in macOS and paste this command to create a bootable macOS USB drive: sudo /Applications/Install\ macOS\ 10.13\ Beta.app/Contents/Resources/createinstallmedia -volume /Volumes/macOS-applicationpath /Applications/Install\ macOS\ 10.13\ Beta.app -nointeraction &say Ready.Rename it to macOS drive or something easy to remember with. Download macOS High Sierra from the Mac App Store and make sure that it shows up in your Applications folder.We will use this to create a bootable USB drive for High Sierra.ĭual boot macOS High Sierra with macOS Sierra Use a fast USB flash drive which should have at least 8 GB storage.At the time of writing, only the first developer preview is out while a public beta is expected later this month.

