Mac OS Download Page To download the 9.0 Client for Mac OS X click here. To download the 8.1 Client for Mac OS 9 click here. Once the installation is complete click here. When the Login screen appears, simply enter your user ID and password and click Login.            For more information about the 9.0 Client for Mac OS X click here. For more information about the 8.1 Client for Mac OS 9 click here. Visit the FirstClass web site to download international clients. IMPORTANT! If you were directed here from the Student Orientation, then this page has opened in a new window. When you have downloaded and installed the FirstClass Client and successfully signed in, you must return to the Orientation page that sent you here and click on the link to Step 4: Email Instructions. That link can be found at the top of the page: