‘APFS disks may not be used as bootable install media’ is a common error while creating a bootable macOS installer. You can fix this error in a couple of simple steps.
While Terminal formats the external disk before mounting macOS, you still need to have it in the right format. You need a Mac OS Extended Disk to make a bootable installer.
What are the different File System Formats on Mac?
macOS supports three major file system formats with sub-formats of their own. Here’s what each file system format stands for and what you can use it for:
- APFS: Stands for Apple File System. This is the default file system for macOS 10.13 or later.
- APFS (Encrypted): This format encrypts the volume and you can secure it with a password.
- APFS (Case-Sensitive): Case-Sensitive formatting allows you to separate folders with the same name based on upper or lower-case naming. For ex, “work” and “WORK” can be two separate folders in this format.
- APFS (Case-Sensitive, Encrypted): Creates an encrypted, password protected, case-sensitive file system.
- Mac OS Extended (Journaled): This is the format you need to create a bootable installer. It preserved the integrity of the hierarchal file system.
- Mac OS Extended (Case Sensitive, Journaled): Creates a case-sensitive Mac OS Extended disk.
- MS-DOS (FAT): You can use this format for Windows volumes with 32GB or less storage.
- ExFAT: Is the ideal format for Windows disks over 32GB. Allows smoother cross-platform usage of the disk.
When will you see ‘APFS Disks May Not Be Used As Bootable Install Media’ error?
When creating a bootable macOS installer, you may see the ‘APFS Disks May Not Be Used As Bootable Install Media’ error. You can see any other format instead of APFS based on the disk you’re using. The easiest fix is to format the disk to Mac OS Extended (Journaled).
Format External Drive for Mac
- Plug in the external drive and open Disk Utilities from Spotlight Search.
2. Go to View and select Show All Devices.
3. Now, Select the External disk you want to format from the sidebar.
4. Hit Erase from the top-right corner of the disk utility menu.
5. Now, give your disk a name and choose the desired format. Select the Mac OS Extended (Journaled) format if you’re creating a bootable installer.
6. Select Erase again, and your disk will format to the desired file system.
Get rid of the ‘APFS Disks May Not Be Used As Bootable Install Media’ error. You can carry on with creating a bootable macOS installer.
If you still see this error, try changing the external disk or shutting down your Mac and start again. Do let us know in the comments if you find this article helpful. We have other macOS tutorials, and lists like the best macOS Monterey features you should try and what is Time Machine and how to use it.