When trying to find a solution for this question, I got the same issue. I believe this is a bug in Selenium.
To achieve what you looking to do, I tried with the JavaScriptExecutor and it worked.
WebDriver driver = new FirefoxDriver();
driver.get("https://mail.live.com/");
driver.findElement(By.name("login")).sendKeys("email@live.com");
driver.findElement(By.name("passwd")).sendKeys("password");
driver.findElement(By.name("SI")).click();
Thread.sleep(2000); // change that as you wish. or use global wait.
((JavascriptExecutor) driver).executeScript("document.getElementsByClassName('t_estc')[0].click();");
What do I here, using JavaScript I get all the emails identified by the class "t_estc" and I click the first element of that array.
This will click the first email in your inbox. If you want to parse all the list, do some logic.