Issues creating Bootable USB for EL Capitan Public beta
I'm trying to follow tutorial over at: http://osxdaily.com/2015/06/11/make-bootable-os-x-el-capitan-beta-install-usb-drive/
to create bootable usb for El Capitan Public Beta, however after completion I get this error in console:
Mount of outer dmg failed.
I tried running
hdiutil verify /Applications/Install\ OS\ X\ El\ Capitan\ Public\ Beta.app/Contents/Resources/createinstallmedia
And it returned:
hdiutil: verify: unable to recognize "/Applications/Install OS X El Capitan Public Beta.app/Contents/Resources/createinstallmedia" as a disk image. (image not recognized)
hdiutil: verify failed - image not recognized
I'm not sure why. I downloaded beta installer and it launched correctly. It sits in Applications folder.
Solution 1:
I tried many things talked about here and on other top Google searches:
- Redownloaded (three times)
- Tried moving the .app to Desktop
- Changed permissions of .app
- Verified the .dmg with hdiutil
- Used different Mac
Eventually got it to work by using a different USB flash drive. My original USB was a 16 GB Kingston, the second I tried that also didn't work was a 8 GB Lexar. The third and final one that did not get the "mount of outer dmg failed" error is a PNY 8 GB.
For reference I used the command:
sudo /Applications/Install\ OS\ X\ El\ Capitan\ Public\ Beta.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install\ OS\ X\ El\ Capitan\ Public\ Beta.app --nointeraction
Solution 2:
I was having this too. I finally had success by copying the install app/folder from /Applications to the desktop. Once there the "mount of outer dmg" message was no more, despite using the same command (other than the appropriate path changes). Might not be the solution for everyone, but it did work for me.
Solution 3:
The only way I was able to get it to work with my SanDisk Extreme 64GB was to format using 'Apple Partition Map' instead of 'GUID Partition Map' before running createinstallmedia.