As I'm sure your developers are aware, this option is not available, nor is there a simple alternative in OS X 10.11 El Capitan. I attempted to resolve it in the same way, through using the First Aid tab in the Disk Utility to modify the access rights. Unfortunately, there is no easy way to call and speak to a support specialists, so after many queries, I was able to find out the message most likely relates to an issue similar to that in one of the strings associate with AutoCAD LT or Mac on OS X 10.8 Mountain Lion.
Contact the Software manufacturer for assistance.' The Installer encountered an error that caused the installation to fail. While trying to install AutoCAD 2015 for MAC, I received the following message: I recently purchase a MAC, with OS X 10.11 El Capitan, and signed up for AutoCAD 2015 for MAC because the website said AutoCAD 2016 for MAC was not supported on OS X 10.11 El Capitan.
