How to ensure that the Browser has been closed

Sorry the link I was referring to was missing when I pasted into my reply

Checking if the Browser Is Running From Scripts

http://support.smartbear.com/viewarticle/33274/#Scripts

The example there is slightly different and uses while statement and WaitBrowser method rather than if statement. Can you try this?

function Check()

 {

  while (Sys.WaitBrowser().Exists)

  // if (Sys.WaitBrowser().Exists)

    Sys.WaitBrowser().Close();

  Browsers.Item(btIExplorer).Run("http://smartbear.com");

 }