Most nights I fall asleep listening to music - sometime during the night, my computer goes to sleep. When I wake it up the next morning, my external audio device (M-Audio Fast Track Pro) get 'lost' somehow. It doesn't appear on the list of available audio devices, it's not in the device manager, it's not in the audio device properties, etc. Turning the device off and then on again doesn't have any effect - stopping and starting
audiosrv doesn't do anything. (and drivers are up to date, naturally, and this issue has persisted through several rounds of updates)
Restarting the computer makes everything work perfectly again - until the next time it wakes up and forgets about the fast track again.