If you have another startup disk with a compatible operating system, your Mac can start up from that disk instead of your current startup disk.
How to choose a startup disk on your Mac to boot from USB A “startup disk” is a volume or partition of a drive that contains a bootable operating system.
You can partition your Mac and boot macOS Mojave alongside High Sierra. Select your hard drive in the Disk Utility window. It will be the first.
Here's how to split your Mac hard drive into multiple partitions or You can now choose to set a storage limit for this volume, but you don't have.
Mac OS X and later with no changes to the partition scheme Layout" or " Volume Scheme:", choose the number of partitions you want to.
To choose the partition map scheme, select the disk (not a volume) and click the It is recommended that you choose APFS or Mac OS Extended (Journaled).
To partition the drive, go to Spotlight at the top of your MacBook Select Partition and create the partitions based on your specific needs. In my.
Creating a Separate Data Partition During Installation OS X and later. Open Disk Utility during installation. Select the hard drive you would like to partition.