My conundrum (any advice would be magnificent)... I currently store my iPhoto library on an external drive. Sidenote: I own a white macbook which I bought in 2008. Mac OS X 10.5.8. Upgraded to 500gb drive a couple years back. Yet when I import, more and more space is still being mysteriously taken up on my hard drive each time. And on the external drive. I took my computer to a local computer store, who installed daisydisk (which had to be run from an external drive they had, since my OS was too old to install it), and they showed me the following, of which I took a screenshot, attached. They said the photos are also being stored on my hard drive, in a hidden folder. They suggested that my OS was corrupted and needed to be reinstalled. Is this absolutely the case? Also, if I am able to stop this duplication, will I need to manually go through all albums/photos in iPhoto before deleting them from my hard drive (to make sure none go missing)? Thanks in advance. p.s. in case it is helpful, here are the steps which I followed when I moved my iPhoto to the external. The iPhoto icon no longer shows up in Pictures. - Copy the iPhoto Library Folder as an entity from your Pictures Folder to the External Disk. - Hold down the option (or alt) key while launching iPhoto. From the resulting menu select 'Choose Library' and navigate to the new location. From that point on this will be the default location of your library. - Test the library and when you're sure all is well, trash the one on your internal HD to free up space.