Game downloading in background

Why can’t I install the full client in one go? I have the option checked for the full client but it’s still downloading in the background and it makes the game unplayable

You can lower the background download speed in the menu, settings, misc. screen to free up more of your bandwidth. It’ll take longer to finish but it should smooth out your performance issues while it does. Otherwise just hang out for a minute until the spinning icon on the topbar dissappears.