If you’re using Windows Vista do NOT use Vista to tag your photos. Apparently, Vista destroys a photo’s metadata if you tag the photo. Microsoft hasn’t said if or when they will fix this but I’m sure they will.
“A bit of bad news about Vista if you’re a photographer. Apparently if you tag a photo’s metadata in Vista, it destroys other important metadata used by image editing apps such as Photoshop. Microsoft’s gotten reports of RAW files generated by Nikon cameras being unreadable after being tagged with Vista or Microsoft’s Photo Info tool.”
Good thing I’ve only used Windows Photo Gallery to view photos.
