How to Set the Startup Volume / Startup Drive/Disk

Setting the Startup Disk

When changing the startup volume, be sure to choose it explicitly or there will be a delay in system booting.

Open System Preferences, then choose Startup Disk to set the desired drive as the startup drive.

All bootable volumes show up in System Preferences => Startup Disk*.

You might want to also disconnect or remove any older boot drives when making a switch, to avoid confusion (this is why using different names is also a good idea).

* Startup Disk is an error in terminology; it’s a startup volume (a disk can have many bootable volumes). Apple has not fixed this terminology bug in decades.

Tip: you can boot off any bootable volume at system startup by holding down the Option key; a list will be presented. Doing so does not change the default.