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

I tried to create a bootable USB Stick an get the following massage from the Terminal : /Applcations/Install OS X El Capitan.app does not appear to be a valid OS installer application.

Does anybody know the Problem ??

If you patiently read through this topic you will find that Kappy's posts have all the relevant information required.

Hi all

I've been trying for hours to create a bootable El Capitan (10.11.3). Downloaded a fresh copy from the MAS, and have followed the instructions in this thread to use the following:

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

and I continue to get the following message:

Couldn't mount dmg /Volumes/OS X Install ESD/BaseSystem.dmg (error code 112)Copying boot files...

Failed to copy kernelcache, The file “prelinkedkernel” couldn’t be opened because there is no such file.

I've tried to restart my MBP (17", early 2011) Holding down Option to bring up the bootable drives, and the USB doesn't show there.

I can't seem to find any information regarding the "Failed to copy kernelcache, The file “prelinkedkernel” couldn’t be opened because there is no such file." error, so I'm wondering if this is purely an isolated result.

I have also tried the suggestion to hold Option and then inserting the bootable USB, but after trying that, it doesn't show on screen.

I'm out of ideas - any help??

josh wilms wrote:

I have also tried the suggestion to hold Option and then inserting the bootable USB, but after trying that, it doesn't show on screen.

I'm out of ideas - any help??

Back in the fifth post down on page 1 I suggested simply installing El Capitan on a USB Flash drive, which would make it bootable. Copy the El Cap installer file on it, boot from the Flash drive and run the installer with your chosen drive as the target. Having a bootable external from which you can run utilities is just a bonus. It's hard to find a small USB Flash drive these days and, indeed, Best Buy is selling a 256GB USB 3.0 flash drive for $60 today.

HI Josh

As a long shot did you follow these instructions from Kappy, and did you have the El Capitan Installer in your applications unused as in a fresh download of El Capitan, because the installer fie is used when you install El Capitan so, you need a fresh one to make a bootable disk ?

I did this and it worked for me:

KappyOct 4, 2015 9:23 AM Re: Cannot create bootable El Capitan USB media using "createinstallmedia" or Diskmaker X
in response to EdisonW

Give this a try. I've tried it and it works.

Make your own El Capitan flash drive installer using the El Capitan tool:

You can create a El Capitan flash drive installer via the Terminal. El Capitan has its own built-in installer maker you use via the Terminal:

You will need a freshly partitioned and formatted USB flash drive with at least 8GBs. Leave the name of the flash drive at the system default, "Untitled." Do not change this name. Wait for the process to complete which will take quite some time.

Open the Terminal in the Utilities folder. Copy and paste the following command line in its entirety into the Terminal window.

sudo /Applications/Install\ OS\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath "/Applications/Install OS X El Capitan.app"

Press RETURN, enter admin password (will not echo to the window) then press RETURN again.

You need to have the installer in your Applications folder or change the paths in the above command line.

I did follow the instructions (several times) but it simply wasn't working. I was using a fresh download of El Capitan, but trying to create the USB whilst in Yosemite. Ideally I wanted to do a completely fresh install of El Cap. by re-formatting my HD and installing El Cap, then using my Time Machine backup to restore my files, however, in the end I gave up and just installed El Cap over Yosemite.

Now I'm re-downloading the El Cap installer and will try (yet again) to make the bootable USB, so I can re-format and then install.

Don't know if this will work for you guys having issues with the boot disk not being recognised or unable to boot from your newly created El Capitan boot disk, but this is what worked for me.

1. I formatted the USB on the same system I was trying to do the clean install on. I.E. format on mavericks if this is the system you want to replace with el capitan.

2. Use this USB on any device to create Boot disk with terminal as explained by Kappy.

3. Now try to boot on the mavericks system.

Hope this helps, I tried multiple ways with the same problem and at last this worked.

Hey. I found a solution.

******** All you need to do is to right click on "Install OS X El Capitan.app" then select -Show package Content. Now Copy "Install OS X El Capitan.app" folder to your desktop. then delete orginal file and replace it with the folder you copied to your desktop.

>>> You Should noticed that after this the icon changed.

I just created another related question

createinstallmedia doesnt install .IAProductInfo ... why?

The basic question... I created two install bootable USB flash drives. One I did earlier this year... and works. The second I did yesterday and it doesnt work.

When I "diff"d them... the only difference was the one that I made yesterday didnt have ".IAProductInfo" on it.

I have no idea why that would be... or how/why one of the installs got it and the other one didnt.

All of the files on the two flash drives are the same... except that one which is missing.

Does anyone have any ideas why?

Thanks,

Alan

> right click on "Install OS X El Capitan.app" then select -Show package Content. Now Copy "Install OS X El Capitan.app" folder to your desktop.

this approach worked for me as well. after I copied the contents of the Yosemite Installer to my desktop, I was able to successfully run this terminal command to create a bootable USB drive on a USB stick named `YosemiteInstaller`

```

sudo ~/Desktop/Contents/Resources/createinstallmedia --volume /Volumes/YosemiteInstaller --applicationpath /Applications/Install\ OS\ X\ Yosemite.app --nointeraction

```

Hi all,

I am having this issue as well. I read the thread but the root cause isnt clear to me (Apple bug?) and the solutions offered didn't work. I had to recently replace the SSD part of a DIY fusion drive in my 2011 IMAC and installing from the recovery drive/web isnt working - the error is ".lastResort" in the log and it just hangs there. So I decided to try the USB Flash drive approach. I tried creating a flash drive using both the methoed outlined by Apple and using Diskmaker X. In both cases I got what looks like a bootable OSX USB drive:

Which I can see in my Disk Utility on both my main machine and the machine I am trying to rebuild:

However I can not see it in the startup preferences on any of my iMacs nor does it appear when I hold down ALT on boot up - I only get the Recovery Drive as an option. I also tried having the USB drive plugged in and out on different reboots to no avail.

Open to ideas/suggestions?

I had exactly the same issue until I found this post in this same thread. Trivial as it may seem, eject the bootable flash drive and reboot holding down Alt. After available startup volumes appeared (your inner disk and the Recovery partition), insert the flash drive. Now you should see it as available startup volume. Not sure if it will work for you, of course, but well worth giving a try. I was about to trash my USB key when I discovered this.

Hi Yeehat, I did try that, but it didnt work. Is it specific to El Capitan? Can I create a OSX Lion USB Flash drive instead?

Thanks.

As you can see, the original user reported this issue as specific to El Capitan (and maybe it makes sense because Apple introduced new restrictions about startup disks in El Capitan, e.g. third-party apps, like SuperDuper!, can no longer programmatically set the startup drive). If your iMac is late-2011 (and not mid-), it came with Lion installed and I actually found advanced users advising to reinstall Lion and then upgrade to El Capitan. See, e.g.:

Can't install El Capitan on new SSD

http://apple.stackexchange.com/questions/230771/installing-el-capitan-on-a-new-s sd

Hope this helps.