There are a few ways of doing this, so you can try various ways and use the method you prefer. Option 1: In the Thread Pane where you see the list of emails, there should be a 'Sort by Star' column header which displays a black five sided star icon. There will be a list of black outlined stars adjacent to each email. In the line that contains the email, click on the black outline of a star and it will turn yellow. Now it is 'starred'. Option 2: useful if email is not opened Right click on email in list to get a drop down list. Select 'Mark' and then select 'Add Star' Option 3: select email to read in Message Pane Right click on content in Message Pane to get a drop down list. Select 'Mark' and then select 'Add Star' Option 4: If you have the top 'Menu Bar' enabled which shows 'File', 'Edit', 'View' etc Select email in list Click on 'Message' and Select 'Mark' and then select 'Add Star' you can also use the Menu Bar via the keyboard Select email in list Hold down 'Alt' key and keep holding it down whilst you type these letters M, then K, then S Option 5: If you prefer to use the Menu app icon (3 horizontal line) Select email in list click on 'Menu app icon' Click on 'Message' click on 'Mark' click on 'Add Star' Please note that to remove a Star, you repeat any of the above instructions and the star is removed.