I have a referenced library where the originals live on the network attached hard drive. I can access the drive perfectly well in Finder, but Aperture hardly ever sees it. I can sometimes get it to recognize the drive by exiting Aperture, accessing the drive in Finder, then reopening Aperture. Sometimes. But sometimes even that doesn't work and I have to reboot. Why can't Aperture see a drive that the rest of the computer can see just fine?