I have a Tascam US-1641 audio card that plugs into my computer via USB. I've used it with over 5 different computers over the years and have always had this problem to some extent, but recently it seems to be worse.
When i turn it on, it shows up in the 'Devices and Printers' but doesn't show up in the 'Sound' section. If i turn it off and on many times (sometimes just once, sometimes 30+ times) it will eventually show up in the 'Sound' section and i can start using it.
I've tried uninstalling the driver and reinstalling it. This has been a problem on multiple different computers.