This error may also appear as the similarly worded "App Name" can't be opened because it was not downloaded from the Mac App Store." depending on the security settings on your computer. A sample of the error is shown below:
These errors are caused based on settings in the OS security. To install the software anyway without changing the security settings on the Mac, follow the steps below:
1. Press CTRL and click the application or driver you are trying to install. Then click "Open" at the top of the list that appears.
2. A new window will appear asking you to confirm the override, click "Open' on this screen.
The software/driver installation will begin.