Important: Before you Install
just:in comes as a disk image (DMG). To open the disk image the Security settings of the system must be changed.
- Open the System Preferences.
- Go to Security & Privacy.
- Click on the General tab.
- Unlock the Preference Pane.
- Change the setting to Allow apps downloaded from App Store and identified developers.
- You can now head to the point Download & Installation below.
Further reading (external link): → macOS Sierra: Open an app from an unidentified developer