Norton 360 deleting game executable that has been on computer for over a year.

All of a sudden Norton 360 is deleting the executable for the Steam game Pool Nation.  I've been playing the game off and on, on this install of Windows (10 Home) for almost a year without problems.  Today I go to play the game and it says executable not found.  I uninstall the game and reinstall and ooops, the executable is deleted again.  Anyone any clues or have you heard of this happening to others?