Whether you’re on PC or MAC OSX, you may have noticed that Google Voice keeps telling you to: “please download the voice plugin to make a call” even after you’ve installed it several times. What’s changed is the old google voice chat plugin is no longer supported (though they don’t even tell us). You have to upgrade to the New Google Hangouts, where a phone call tab exists there.
To do this, on the left hand side of gmail you’ll see a green dot next to your name on the chat window. There’s a small DOWN arrow, which you can click and the first option will say “Try the new Hangouts”.
Once you click that it’ll work again. Presto!