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Level 1

28 points

Cannot create bootable El Capitan USB media using "createinstallmedia" or Diskmaker X

Hello all,

So far (knock on wood) El Capitan has been fantastic on my 2011 MBP 13" i7, and has actually improved everything, especially performance. Some minor glitches here and there but I was expecting it.

However, one BIG thing I've come across is this... Whenever I go to try and create a bootable USB installer using either the embedded "createinstallmedia" command found within the El Capitan package, or using Diskmaker X v5.0, both methods successfully create the USB installer, but neither method generates a USB device that I can select as a Source Disk in System Preferences, nor will it recognize as a bootable device when I hold down the Option key starting my Mac.

I've tried using 4 different, reputable brands of USB sticks, ranging in size from 8GB USB 2.0's to 32GB USB 3.0's, no effect, and I've tried them on 4 different models of Mac's, all on the certified El Capitan compatibility list. Each machine won't recognize it as a bootable source.

My first attempts at making the USB's were actually while the Mac was still on Yosemite, so I don't think this is a El Capitan bug. It almost seems like the image created from the package doesn't contain the boot components.

Has anyone else here experienced this issue, or possibly found a way to fix this and make it work? I have three Mac's with blank drives I'd like to put onto El Capitan, but can't until I manage to create a bootable USB.

Thanks in advance!

MacBook Pro, OS X Mavericks (10.9.2), 16GB RAM / Samsung 840 Pro SSD

Posted on Oct 2, 2015 11:00 AM

64 replies

Oct 4, 2015 9:54 AM in response to Kappy

Hi Kappy - it seems like you're more concerned with being "right" than with helping, but arguing about it here is unlikely to change your behaviour.

The original poster, and several others on this thread, are trying to figure out why the method you described, which we have all used successfully, does not create a bootable USB drive for us.

As part of the troubleshooting process, some of us created bootable USB drives from other versions of OSX using the createinstallmedia utility on the same USB drives that aren't working for El Capitan.

Oct 4, 2015 10:00 AM in response to EdisonW

The older method for booting off of a DVD or USB was to hold the C key on boot up.

I wonder if that works in this situation with the SDcard created via /createinstallmedia command.

It seems a step backwards

Kappy

Level 10

361,741 points

Oct 4, 2015 10:04 AM in response to leroydouglas

No, it merely tells you the device is properly formatted and partitioned. To be bootable requires the installation of a bootable OS X system. The system installed determines if the device is bootable.

If you want a proper list then use 'diskutil cs list' because the drive is setup using CoreStorage.

Kappy

Level 10

361,741 points

Oct 4, 2015 10:05 AM in response to leroydouglas

Booting from media other than the CD/DVD requires using OPTION boot:

Boot Using OPTION key:

1. Restart the computer.

2. Immediately after the chime press and hold down the

"OPTION" key.

3. Release the key when the boot manager appears.

4. Select the desired disk icon from which you want to boot.

5. Click on the arrow button below the icon.

Oct 4, 2015 2:19 PM in response to EdisonW

EdisonW Oct 2, 2015 11:00 AM

but neither method generates a USB device that I can select as a Source Disk in System Preferences,

I did not see this option in the System Preferences>StartUp Disk either, if that is what you are referring to, however when I reboot my machine with the option key held down it is present.

I did not seem to have a problem using the /createinstallmedia command to make a bootable Back-Up Installer.

EdisonW Author

Level 1

28 points

Oct 4, 2015 2:19 PM in response to EdisonW

So after more testing, I've discovered the following...

I still can't get El Capitan USB media to recognize as bootable sources under Source Disks in System Preferences no matter what I try.

I have, however, been finally able to get Macs to recognize the media at boot up... The trick is to boot the Mac holding the Option button, but NOT having the USB stick in the machine at startup. Instead, when the Mac boots to the volume selector screen, then insert the USB stick, and within a few seconds it WILL show up as a bootable external device. I have managed to get all my remaining Macs upgraded to El Capitan directly from the USB stick.

This shows the created media is bootable, but for some reason won't recognize from within the OS, nor if intserted at startup.

I am curious to see if this will work for the others here that have chimed in with the same problem I had, and if it will finally get them going...

Cheers

Oct 4, 2015 2:24 PM in response to EdisonW

EdisonW wrote:

nor if intserted at startup.

I did not have this problem.

You can always send feedback to Apple or if you believe it is a bug- file a report.

Apple Feedback http://www.apple.com/feedback/

Bug Reporter https://bugreport.apple.com/

Oct 4, 2015 2:34 PM in response to leroydouglas

Hi Leroy - couple questions:

- did you create the backup installer from a machine that had El Capitan installed on it already?

- did you try using a USB drive as well as the SD card?

cheers

dave

Oct 21, 2015 10:02 AM in response to EdisonW

EdisonW - that worked for me as well.

Oct 8, 2015 8:33 AM in response to Ghost_Rider

Hi Ghost_Rider

Thanks Your suggestion worked. The final message in Terminal was as follows below but the drive works as a bootable disk when I checked it: I asssume that because the ends of the command is --nointeraction that the mounting part is curtailed:

Last login: Thu Oct 8 15:34:11 on ttys000

Martin:~ Admin$ sudo /Applications/Install\ OS\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia --volume /Volumes/ElCapInstaller --applicationpath /Applications/Install\ OS\ X\ El\ Capitan.app --nointeraction

Password:

Erasing Disk: 0%... 10%... 20%... 30%...100%...

Copying installer files to disk...

Copy complete.

Making disk bootable...

Couldn't mount dmg /Volumes/Install OS X El Capitan/Install OS X El Capitan.app/Contents/SharedSupport/InstallESD.dmg (error code 110)Mount of outer dmg failed.

Done.

Martin:~ Admin$

Oct 8, 2015 10:36 AM in response to martin from

Ah! When I restarted and pressed Alt the memory stick bootable drive was not there so, I did the following:

I erased and formatted usb drice memory stick again and renamed it "Untitled" in Finder.

Ithen issued this Command in Terminal:

Admin$ sudo /Applications/Install\ OS\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia –volume /Volumes/Untitled –applicationpath /Applications/Install\ OS\ X\ El\ Capitan.app

So:

Last login: Thu Oct 8 16:40:30 on console

Martin:~ Admin$ sudo /Applications/Install\ OS\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia –volume /Volumes/Untitled –applicationpath /Applications/Install\ OS\ X\ El\ Capitan.app

Password:

You must specify both the volume and install application path.

Martin:~ Admin$ sudo /Applications/Install\ OS\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia –volume /Volumes/Untitled –applicationpath /Applications/Install\ OS\ X\ El\ Capitan.app

You must specify both the volume and install application path.

Martin:~ Admin$ sudo /Applications/Install\ OS\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install\ OS\ X\ El\ Capitan.app

Ready to start.

To continue we need to erase the disk at /Volumes/Untitled.

If you wish to continue type (Y) then press return: Y

Erasing Disk: 0%... 10%... 20%... 30%...100%...

Copying installer files to disk...

Copy complete.

Making disk bootable...

Copying boot files...

Copy complete.

Done.

Martin:~ Admin$

The saliant point was to leave out the -- noninteraction at the end of the command

If I now turn off my iMac and restart and press Alt the bootable drive shows up in the drives available and I can proceed from there.

Oct 8, 2015 11:06 AM in response to martin from

martin from wrote:

The saliant point was to leave out the -- noninteraction at the end of the command

If I now turn off my iMac and restart and press Alt the bootable drive shows up in the drives available and I can proceed from there.

But the question really is, do you see it in >System Preferences>Startup Disk ???

Oct 8, 2015 2:03 PM in response to leroydouglas

Oh! Right. I now see the problem. I've spent quite a lot of time on this including talking to several senior techies at Apple and they could not figure out it so, the assumption by them was that something in El Capitan prevents us making a bootable drive but they had no idea why. One of the really annoying aspects of Apple is that when something like this comes up on the forum they do not just put up a statement telling us how to do it or why it cannot be done.

As everyone has said this was a doodle in Yosemite and so, it is reasonable for customers to want to do the same in El Capitan. It may not be practical for Apple to use disks anymore, however, when we are reliant on Apple's servers and software that does not respond to doing something useful, like a bootable drive, I personally miss having disks that I can use to get a system up and running again.

Oct 8, 2015 2:45 PM in response to martin from

Having read through the extended struggle to create a bootable installer, it still seems easier to install El Capitan on the flash drive and then copy the El Cap installer to its Applications folder so that you can not only run the installer from there but use that external drive for other purposes (e.g., running programs beyond Disk Utility, such as Carbon Copy Cloner or Disk Warrior) and have it appear in Startup Manager like any other bootable drive.

Oct 8, 2015 3:22 PM in response to FatMac-MacPro

I do not understand what you mean by, " install El Capitan on the flash drive and then add El Cap Installer to its application folder?" El Capitan itself surely is a very large file and is not going to fit on a flash drive?

I just tried the same Terminal Command that I used before but with "--nointeraction" at the end of the command and it resulted in this:

Last login: Thu Oct 8 22:22:01 on console

Password:

Erasing Disk: 0%... 10%... 20%... 30%...100%...

Copying installer files to disk...

Copy complete.

Making disk bootable...

Couldn't mount dmg /Volumes/Install OS X El Capitan/Install OS X El Capitan.app/Contents/SharedSupport/InstallESD.dmg (error code 112)Mount of outer dmg failed.

Done.

Martin:~ Admin$

Cannot create bootable El Capitan USB media using "createinstallmedia" or Diskmaker X