I am using OS X El Capitan on Macbook 7.1 (Mid-2010). My thumbdrive is detected inside El Capitan and I can make it bootable and put El Capitan installation on it by using terminal command:
sudo /Applications/Install\ OS\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install\ OS\ X\ El\ Capitan.app --nointeraction
but thumb drive is not visible when I hold option on restart. Therefore I can't install El Capitan on my new SSD that I have. When I install using terminal, I get this message at the end of the process, in terminal:
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.
After this, when I ran the hdiutil:
hdiutil verify Install\ OS\ X\ El\ Capitan.app/Contents/SharedSupport/InstallESD.dmg
on the thumb drive, I got:
Checksumming Protective Master Boot Record (MBR : 0)… Protective Master Boot Record (MBR :: checksum failed with error 1000. …………………………………………………………………………………………………………………………………………… calculated CRC32 $00000000, expected CRC32 $BE5D6293 hdiutil: verify: checksum of "Install OS X El Capitan.app/Contents/SharedSupport/InstallESD.dmg" is INVALID hdiutil: verify failed – image data corrupted
So the error can be either on the installation or the thumb drive itself (bad drive).
Sometimes I get this message at the end of the installation thumbdrive making process:
Failed to copy kernelcache, The file “kernelcache” couldn’t be opened because there is no such file.
I want to install fresh clean install of El Capitan on my brand new SSD that I bought, and somehow Apple is preventing me from using it. Any help anyone?
Best Answer
Open Terminal and check the hash of InstallESD.dmg:
The result (as of March, 5th 2016) should be: 526a6f7a619ef86f42acc026276aab351ea27614
Get the disk identifier of the thumb drive with
Below I assume the disk identifier of the thumb drive is disk1
Delete any MBR on the thumb drive:
Open Disk Utility and partition the thumb drive:
Options...: GUID partition table
Name: Untitled
Format: Mac OS X Extended (Journaled)
Create the El Capitan Installer thumb drive:
The output looks like this:
Check the InstallESD.dmg on the thumb drive:
The output should look like this:
Some of the CRC32 values may be different in your output!
Reboot you Mac with the thumb drive attached and hold the alt/opt button. If the thumb drive doesn't show up on the first run just repeat the step. It took me 2 tries to successfully boot to the installer thumb drive.