I don't know how rainmeter does that but Windows APIs querying if drive is ready are horrible, and I've seen it freeze thread - UI or threadpool, whether disconnected drives, some external HDDs, even empty card readers. OC can show those, but it is intentionally removed as it slows down the entire system (not only OC, even in Explorer, Open/Save dialogs will turn $5K PC into a 386). I've spent days on it and don't have a good solution. I have a few more ideas but I am not sure when I'll get to that, as there is not a good chance it will work in a satisfactory way.