Looks like no one’s replied in a while. To start the conversation again, simply ask a new question.

What is the correct format for an external disk that I want to use as a bootable disk

I followed the Apple instructions for creating an external bootable disk on my MacMini running the latest version of Catalina but when I want to use it , it said I cannot use this as the volume is not formatted as APFS but your instructions above say to format as Mac OS Extended

Posted on Jun 18, 2020 8:33 AM

Reply
Question marked as Top-ranking reply

Posted on Jun 18, 2020 8:43 AM

George Colpitts Said:

What is the correct format for an external disk that I want to use as a bootable disk. I followed the Apple instructions for creating an external bootable disk on my MacMini running the latest version of Catalina [...]

———-


For Which Operating System?

APFS is for High Sierra (macOS 10.13 and later).


So, if it is asking you to use MacOS Extended, then you may be using too old of a Mac (before 10.13) to create it, or you may be installing an older Operating System.


4 replies
Question marked as Top-ranking reply

Jun 18, 2020 8:43 AM in response to George Colpitts

George Colpitts Said:

What is the correct format for an external disk that I want to use as a bootable disk. I followed the Apple instructions for creating an external bootable disk on my MacMini running the latest version of Catalina [...]

———-


For Which Operating System?

APFS is for High Sierra (macOS 10.13 and later).


So, if it is asking you to use MacOS Extended, then you may be using too old of a Mac (before 10.13) to create it, or you may be installing an older Operating System.


What is the correct format for an external disk that I want to use as a bootable disk

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple Account.