If you hover over a drive that is not currently available, it is normally a harmless error condition. Power Drawers usually handles it smoothly by simply changing the menu item for that drive to be dimmed and include the text "(unavail)" to indicate that the drive can't be accessed at that time. An example would be right-clicking on My Computer and hovering over a floppy drive while no disk is in the drive. 

Normally this is a harmless condition that doesn't cause a crash. However, if you have a special virtual drive (for example, for a digital camera) and the drive is not available at the time, then hovering over it might cause an unexpected error or crash. The short-term solution is not to hover over such drives if you know they are not available at that time. If you move the mouse quickly past that item on the menu, it will not try to open the drive and trigger the error condition. When the drive is actually connected, you will be able to access it normally with no problems. We are working on a better technical solution for this rare error condition.