This error is caused by the Gatekeeper Security feature included in OS X 10.8 (Mountain Lion) and above.
To bypass this issue and alert, open System Preferences and click Security & Privacy.
Change “Allow apps downloaded from” to Anywhere.
Once your are done, try running the installer again.
If you prefer to keep Gatekeeper on, you can always revert this setting to default after installing our product.
For newer operating systems (OS X 10.13 and up) like Catalina, Mojave, Sierra, High Sierra
The app you’re installing will appear under the “Allow apps downloaded from” menu.
Click “Open Anyway” next to this and your software installer will launch.