Why does my Sibelius 8 have no sound?

When I launch it, it says “Error: 40201 – Undefined external error (MMSYSTEM/OUT)” and then there’s no sound, not that there was any sound before. After it launches there’s no sound when I notate, so I check the “Playback Devices” (attached picture). I’ve also made sure that “Use virtual instruments and effects” was checked in Audio Engine Options. What’s going on? Why isn’t Sibelius working?

If you are not using a dedicated external interface, try installing ASIO4ALL.

That adds low-latency drivers for the normal PC sound system; some programs will not run without an ASIO compatible interface.

http://www.asio4all.com/