I just noticed that Voila is not performing screen captures in Mountain Lion for me. I thought the existing library might be too big (~500 mB), so I created a new Library in the same folder, but it still does not capture for me. I tried both double-clicking on the selected area, and clicking on the camera icon .. neither brought up the Voila page. Bring it up manually, does not show the desired screen capture. Ditto for capturing an object and fullscreen.