I had no issues with Windows. Whenever I plug in HDMI and the receiver is on, it automatically plays. If it doesn't, I type 'sound' on the start menu which brings up the control panel sound icon. I then just 'right click' the HDMI to make it a default. That way when you unplug the HDMI it'll go back to the previous choice.
If you are lucky you can choose which to output from the volume control on the notification. That doesn't always work on all laptops I own, but the sound control panel always does.