I have my iPhoto library on an external HD made by Seagate. I just tried to open the app and it says it can't locate my library, so in doing a search for this drive, I get no files visible on the drive. Yet looking at drive info, it knows the drive is about half used and the rest is free. Do I have a damaged HD and if so, what do I do next? Sure wish I had backed up ALL my photos somewhere else........