Making a bootable USB "Mount of outer dmg failed"

[Macs4u]

Hi,

Currently running Yosemite and trying to create a bootable USB drive for El Capitan so i can put a clean install on. It keeps throwing up the Mount of outer dmg failed" at the end. Ive tried everything i can think of to rectify it but can't.

Could i create another partition, install El Capitan on that an then delete Yosemite's partition when I'm in El Capitan?

Matt

 

[MrNomNoms]

Hi,

Currently running Yosemite and trying to create a bootable USB drive for El Capitan so i can put a clean install on. It keeps throwing up the Mount of outer dmg failed" at the end. Ive tried everything i can think of to rectify it but can't.

Could i create another partition, install El Capitan on that an then delete Yosemite's partition when I'm in El Capitan?

Matt

I had the same issue however I did an upgrade to El Capitan then I created a bootable USB drive in El Capitan and the error didn't occur so I'm unsure why it happened.

 

[tywebb13]

That's interesting. Several workarounds have been found and are in this thread already: https://forums.macrumors.com/threads/el-capitan-pb1-bootable-usb.1899261/ the easiest one being to use a 16GB USB3.

But it is good to know that el capitan itself can handle createinstallmedia more successfully than other systems in this instance.