Starting the blizzard app then navigating to a specific game either by shell execute or by a web browser typing in the battlenet:// or blizzard:// protocol with a game results in the game receiving it as a command line argument. For example typing “battle.net://WoWC” will navigate to the WoW Classic page and clicking play will result in an exception due to WoWC:// being set as a command line param of the wow executable. This works fine for the more modern games as they seem to ignore malformed parameters; however classic throws an exception.