If Youtube or other audio/video playback apps don’t work while your DAW is open, then there is most likely a sample rate mismatch between the DAW session and the WDM sample rate (i.e the System sample rate set in the Control Panel > Sound > Playback > Properties > Advanced). Set the System sample rate to match the rate of your DAW session.
My Youtube video won’t play on my Windows computer and Apogee interface, how can I resolve this?