If “Scarlett 2i2 USB” does not show up in Audacity here
the Focusrite interface needs to be put into “Class Compliant Mode”. First, click this link in order to download a zip file, when prompted make the following selections
and the file should extract itself to your Downloads folder. Then, right click or control click on the file and select open, the file will only allow you to open it via this method, double clicking on it will not work. At the following window, select “Open” and follow the prompts which will instruct you to unplug the Focusrite (the red box) and prepare to restart your computer. After the computer is restarted, you can plug the Focusrite back in and quit the ClassCompliantMode installer when it pops up again. If the installer requires administrative privileges, come to the lab during the hours listed on the door and one of the assistants can help you install it.