>Hmm, I tried "windows explorer" "drive information" "api calls" but couldn't quickly find any hard-core code samples. There was one message from someone who has the same problem as you, though - but no answer :(

Do you have the reference of that page?

>I'm not sure WMI is the way to go with this. The Windows Explorer functions predate it, the calls are probably older/simpler/lower level.

Yes, correct, WMI has probably reached its limit in regards to it. Another path would have to be considered for such need.