This warning appears due to downloading the app from the Internet. If you downloaded the app from our website, this is normal.
To open the app on Windows you can press “More info” in the warning screen and then “Run anyway”.
On macOS, you may need to right-click the app and select “Open” INSTEAD of just double-clicking the app to open. Doing it from the context menu lets you choose “Open” again in the question dialog that appears.