EDIT. It is now back to normal. I switched the Ayre to USB 2 and loaded their driver, and it didn't work. I shut down then restarted the PC and then it did all work. phew!!!!
Ayre QB-9 USB DAC, Win 7 64 bit, MC18.0.206, drivers for 192 not loaded.
I was away last week and the PC and indeed whole system was off. I think when I first turned on the PC and ran MC it installed an update, before I played anything. Then when I tried to play (using a dCS Debussy at the time) everything appeared to be working, sound meters bouncing up and down, blue light for direct came on, sample rate indicators changed on DAC according to selected music but no sound. I isolated a problem in the DAC (at least I thought I did), so switched to the Ayre DAC, but still have exactly the same symptoms. Other programs play sound and so will MC if I select Direct Sound, but no sound at all from WASAPI.
What has happened while I was away??!! More importantly, what do I need to do about it? I have tried just about every combination of settings, but they ether make no difference or produce an error message that the format cannot be played.