When you are installing Maple or MapleSim on your Macintosh, if you are told that the installer 'is from an unidentified developer' or the 'identity of the developer cannot be confirmed', or you receive a similar message, likely Apple's Gatekeeper is halting the installation. To remedy, please try the following:
Locate the installation file in Finder. It is probably something like:
Either "control-click" or "right-click" the file instead of double-left-clicking the file.
Press "Open" in the resulting dialogue box. The installation program should now be running.
Alternatively, you can make the following global settings change:
Apple icon > "System Preferences" > "Security & Privacy" > "General" > "Allow apps downloaded from" > "Anywhere"
Starting with Mac OS X 10.13 (High Sierra), the "Anywhere" option is, by default, not visible in the "Security & Privacy" settings page. To make it visible, you can open a Terminal Window and execute the following:
sudo spctl ––master-disable
Variations of the above warning include:
"Maple... " can't be opened because it is from an unidentified developer. "Maple... " is an application downloaded from the Internet. Are you sure you want to open it? "Maple... " is not from the App Store. Are you sure you want to open it? "Maple... " can't be opened because it was not downloaded from the App Store. "MapleSim... " is damaged and can't be opened. You should move it to the Trash. "MapleSim... " is damaged and can't be opened. You should eject the disk image.