By default MAC OSX prevents opening applications that are not in the official App store. There are 2 workarounds for this issue.
- Go to the Finder and locate the Cura software.
- Right-click on the Cura logo and then choose ‘Open’ from the dropdown menu.
- Click ‘Open’.
- Open ‘System preferences’.
- Open ‘Security and Privacy’.
- In the ‘General’ tab, set ‘Allow apps downloaded from:’ to ‘Anywhere’.
This is only required the first time you use Cura. After this you can open the application in the regular way.