Portal 2: Do you use a non-default Steam setup (for example Portal 2 not installed in the Steam directory)? For Portal 2 the optimizer may rely on the game being in the default location (not 100% sure currently). So it may fail when you use a custom directory.
If applying the optimizer settings fails for a game, you can usually apply the most important setting (FOV) manually. Googling FOV + game name in many cases brings up easy to follow tutorials.
Just in case: Steam or not, for many games the optimizer can only work correctly for legit game versions.