APFS disks may not be used as bootable install media.

[bobgall]

I have just installed Mojave and I want to make a bootable USB installer. I tried to follow all the instructions I could find. I formatted the USB as Mac OS Extended. My boot drive is an HDD which Mojave reformatted as APFS. When I initiate a createinstallmedia with the proper agruments I get this error: APFS disks may not be used as bootable install media.
I haven't been able to see how to correct it. Help much appreciated.
Bob

 

[CoastalOR]

What instructions did you use?
What were the "createinstallmedia with the proper agruments" that you used?

If done properly, the process of using createinstallmedia in Terminal formats the USB thumb drive before it creates the bootable installer.

 

[bobgall]

Thanks for your reply.
I copied the command line from the Apple site. I used the install file that was in my Applications folder, left after I installed Mojave. I formatted the USB as I said, OS Extended.
I have done this before with High Sierra, and I was able to create a useable USB install drive.

But I got the error message. About not being able to use APFS. The only thing that's APFS now is the boot drive, which was formatted that way as part of the Mojave install.

I'm puzzled as to why it wouldn't work. The other advice that seems to be be common is to use DiskmakerX.
Bob

 

[Nermal]

createinstallmedia should reformat the USB drive, so that error message seems really strange! Just to clear up any doubt, can you please copy/paste the exact command that you used?

 

[CoastalOR]

Thanks for your reply.
I copied the command line from the Apple site. I used the install file that was in my Applications folder, left after I installed Mojave. I formatted the USB as I said, OS Extended.
I have done this before with High Sierra, and I was able to create a useable USB install drive.

But I got the error message. About not being able to use APFS. The only thing that's APFS now is the boot drive, which was formatted that way as part of the Mojave install.

I'm puzzled as to why it wouldn't work. The other advice that seems to be be common is to use DiskmakerX.
Bob

It is hard to help if you do not provide requested information.

Since you used "the command line from the Apple site" then I guess that must have been;

sudo /Applications/Install\ macOS\ Mojave.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume/

From Apple Site:

Create a bootable installer for macOS - Apple Support

Use an external drive or secondary volume as a startup disk from which to install macOS.

support.apple.com

Was your USB thumb drive named "MyVolume"?

 

[bobgall]

It is hard to help if you do not provide requested information.

Since you used "the command line from the Apple site" then I guess that must have been;

sudo /Applications/Install\ macOS\ Mojave.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume/

From Apple Site:

Create a bootable installer for macOS - Apple Support

Use an external drive or secondary volume as a startup disk from which to install macOS.

support.apple.com

Was your USB thumb drive named "MyVolume"?

No, I put in the name of the volume. As I said I have done this successfully before. Every thing was the same except that the format of the disk with the Applications file was now APFS.

 

[Quackers]

I have just installed Mojave and I want to make a bootable USB installer. I tried to follow all the instructions I could find. I formatted the USB as Mac OS Extended. My boot drive is an HDD which Mojave reformatted as APFS. When I initiate a createinstallmedia with the proper agruments I get this error: APFS disks may not be used as bootable install media.
I haven't been able to see how to correct it. Help much appreciated.
Bob

You say
"My boot drive is an HDD which Mojave reformatted as APFS"
Mojave (presumably Disk Utility in this case) can only do what you tell it to. You must have told it to reformat your boot HDD and perhaps missed that the type was set to APFS. Maybe try that again and restart the process.

 

[DeltaMac]

And, it still sounds like you are trying to use the boot drive as the destination for the install. That's just where you have the installer app. Can you post the actual terminal command that you used, and NOT the sample command that you posted?
You could also follow (exactly) some steps that give you the same result, but makes it hard to make mistakes when using the terminal:

Make installer bootable on flash drive:
Insert your USB flash drive (use a 16GB flash drive for this). Erase that thumb drive, using your Disk Utility. Make sure it is formatted Mac OS Extended (journaled), and the partition Map is "GUID"

The Mojave installer app (Install macOS Mojave) should be in your Applications folder.

Right click on that installer app, and choose "Show Package Contents". Open the Library, then open the "Resources" folder. Leave that alone for a moment...

Launch your Terminal app, then type sudo, and add a single space.

From the Resources folder that you left open, drag the file "createinstallmedia" and drop it on your terminal window. You will see the full path to that file appear next to sudo.

Next, type --volume, and add one space to that. (notice there are TWO dashes, not just one)

Now, find the icon for your flash drive (the one you just erased. Should be on your desktop somewhere). Drag that icon into the terminal window. You will see that disk, with its path, added to the line you have been typing.

AND, press enter. You will be asked to enter your admin password. Do that, you will NOT see what you type (it's a security feature, just type your password, then press enter. It will work.

Finally, the terminal will ask you to press "y" to start the command that you just typed, so type Y, and press enter.

Then, you will see some numbers appear, showing the progress of the command. Some flash drives will be slow, maybe 30 minutes. It will get to 100%, then do a few final items to complete the installer and make it bootable. And, it's ready to go!

There's another app that I think gives more stable results than DiskMakerX.

Make a Bootable USB macOS Installer Download the update for Big Sur compatibility -

What’s needed for a clean install on a Mac A backup of the disk before it’s erased. Two options are to use Duplicate (a free utility which can copy and paste an entire bootable volume), or Mac Backup Guru (a paid, fully featured backup utility with unique incremental backups capability) for...

macdaddy.io

I have used it recently to make each bootable installer from Mavericks to Big Sur. I find it works for any of those. That gives you another choice, if you continue to have challenges with the terminal

 

[joevt]

Show us the command you used.
Show us the output of diskutil list
Show us the output of mount
Tell us which disk is the USB you want to modify.

 

[bobgall]

Thanks to all who replied. I appreciate the help. I always prefer to use the native tools of my devices, but yesterday I decided to use DiskmakerX and it worked entirely as advertised.
Thanks again,
Bob

 

[jbarley]

Thanks to all who replied. I appreciate the help. I always prefer to use the native tools of my devices, but yesterday I decided to use DiskmakerX and it worked entirely as advertised.
Thanks again,
Bob

Glad it worked out for you.
Now maybe mark this thread as "Resolved"

 

[chrfr]

Thanks to all who replied. I appreciate the help. I always prefer to use the native tools of my devices, but yesterday I decided to use DiskmakerX and it worked entirely as advertised.
Thanks again,
Bob

Presumably this worked because DiskmakerX reformatted the disk as HFS+. MacOS installers need to be on HFS+ drives.

 

[Fishrrman]

OP wrote:
"Thanks to all who replied. I appreciate the help. I always prefer to use the native tools of my devices, but yesterday I decided to use DiskmakerX and it worked entirely as advertised."

Which is why I usually suggest that one should try either DiskMaker X or Install Disk Creator first.

Easier than trying to "build the correct terminal command".

And chrfr is right about using HFS+ instead of APFS on a bootable installer drive.

 

[bobgall]

JBarley suggested I mark this as Resolved. But I don't see where to do that. At this point my issue is solved.
Bob

 

[jbarley]

JBarley suggested I mark this as Resolved. But I don't see where to do that. At this point my issue is solved.
Bob

In your original post, upper right area, click on the dropdown menu and select "Edit thread".

 

[CoastalOR]

JBarley suggested I mark this as Resolved. But I don't see where to do that. At this point my issue is solved.
Bob

On a thread that you started;
Click on the 3 horizontal dots on the right side above your 1st post:





Select "Edit thread" > "(No prefix)" pull down > select "Resolved"



EDIT: I took too long making my post, jbarley beat me.

 

[jbarley]

EDIT: I took too long making my post, jbarley beat me.

Yes but, you did a more thorough job. ?