This is because you have not installed the Viewer application correctly. You must be logged on as an administrator of the computer for the file associations to be successfully registered.
You can either re-install the Viewer whilst logged on as an administrator or follow the steps below:
- Open Applications from the Finder > Go menu, and choose Locklizard Safeguard Viewer;
- Once open, the title across the top of the Mac screen will say “Locklizard Safeguard Viewer”;
- From here click File, Open. Then locate the course material;
- Open the desired PDC document from here and it will open in the viewer.