This is a very annoying "feature" of my Mac. Others have asked how to disable this message and have only received answers like "you can't do it without disabling all system messages". I have an Ironkey password protected USB drive. Each time I log into the drive, I get this annoying message, which I then have to click on. The underlying reason for this message is that Mac's must use caching and not write everything to the drive when asked to do so. If this is the case, then how do I disable caching? BTW, most good USB drives have LED lights that indicate when it is safe to remove the drive.