A friend of mine tried to move her entire iphoto library (8,000+ images) to a new location on her computer. She did so by trying to copy all files to the desktop without putting them in a folder. The images were partly copied to the desktop, but could not be displayed for obvious reasons due to the number of files she was moving. The files never showed up on the desktop, but when you open the hard drive and click on the desktop in the left corner of the window, it shows there are over 8,000 files on her desktop that are all zero bytes, and will supposedly open in preview.app if opened. The files don't open, and when you try to delete them, they each say that the file is being used by another application. A bit of a pain to click 8,000 times to delete these files.
Have tried moving all of her actual photo files to a new location to clear the problem, along with a bunch of other little tweaks. Nothing has worked yet.