Downloading Viewer on a Mac results in problems opening and running the installer. How do I fix this?

In some Mac environments, the Viewer installer may give a "broken" or "unidentified developer" warning. This is an indication that the installer has been quarantined by your system. To correct the issue, from a command line, execute the following command:

$ xatttr -d com.apple.quarantine spv2018965macos_setup.dmg

Then, you will be able to run the installer.