I just installed Mac SAFE on HS 10.13.3 and the installation was successfull as far as I can tell. I can see the System Preferences pane and there is a "F-Secure Mac Protection" process in Activity Monitor. However, there is no menu bar icon and I cannot launch the application from Finder. Finder says it is not responding:
A little progress: After I manually added the app to the login items it started showing up in the menu bar after a couple of reboots. Only the first option "Open F-Secure SAFE" is active, but it doesn't do anything. All the others are grayed out. I still can't launch the app manually either. I haven't found a way to log in to my account so it would do something useful.