El Capitan

If you plan to update your Mac to El Capitan beta (10.11) you will not be able to run Xcode 6.4 anymore without some tricks. To get it running again you have to perform the following steps – Warning: With the following steps you may harm your system and you do this on your own risk!

• Copy the file /System/Library/CoreServices/CoreTypes.bundle/Contents/Resources/Exceptions.plist to your desktop
• Open the file with a Plist editor that supports the plist-binary formst (Xcode for example)
• search for Xcode – (case sensitive)
• Change the entries HardDisabled to NO in both search results
• Save the file
• That was the easy part 😉

As Apple has introduced a new security system (System Integrity Protection – SIP) in El Capitan, you have to disable it:

• Open a terminal
• Change the boot-attributes in the NVRAM: sudo nvram boot-args='rootless=0'
• Restart your machine now
• Press CMD+S to restart in single user mode
• Go to the directory /System/Library/Sandbox
• Edit the file rootless.conf with sudo pico rootless.conf
• Look there for the entry booter /System/Library/CoreServices and change the booter to a *
• Save the file and reboot with shutdown -r now
• Now you can boot into the familiar OS X graphical UI.

Last steps to perform:

• Overwrite the Exceptions.plist file in /System/Library/CoreServices/CoreTypes.bundle/Contents/Resources/ with the edited version on your desktop (see above) – this is possible now
• Despite the fact, that there is still the forbidden icon on top of the Xcode 6.4 app icon you can run it – after another restart the icon appeared without the forbidden sign on my machine
• To secure your system again you should change the rootless parameter again: sudo nvram boot-args='rootless=1' in the Terminal and restore the rootless.conf file to its original content (see above)
• That’s it!