I indeed see in the Console that OSX creates a sandbox when I double-click on the NetLogo 6.app: The resulting Read-only sandbox prevents a files from ever being written.
The anti-malware feature launches a new application in a read-only sandbox, if the app is launched from its original folder/location or if it was not moved directly to the root of the Applications folder(no sub folder). In MacOS Sierra 10.12, Apple introduces a feature(headache) called 'Gatekeeper Path Randomization'. Since I have not received any reaction from the list, I have tried to find the cause of this problem, and one culprit I have been able to locate seems to be linked to the fact that NetLogo.App is in the NetLogo folder and Gatekeeper does not like it:
I have already signaled the fact that when I double-click on NetLogo6.app, the icon appears and disappears on the screen, without launching the program. One user wrote in a very well-researched email: We've had several users express problems opening in Sierra.
