I have a 500GB MyBook which loaded an invisible "shadow" file on my G4 PB. The file contains nothing, but take up nearly 19GB (wow!) of space which is NOT available to my computer! That means I actually have only 41GB of data, but my Mac thinks it has 59GB! Is there any any way to delete this invisible file, without erasing my HD and starting over? Only Unix commands by a Genius Guy were able to locate the problem. Any similar problems? This just happened with no notice.