Today’s Question: I have 98,000 photos in my Lightroom catalog. When I select all and use the Save Metadata command I get a message that some photos have been changed in an external application. Should I choose Cancel or Overwrite?
Tim’s Quick Answer: If you are confident that the Lightroom catalog reflects all of the metadata for your photos, you can choose the Overwrite option. If you’re not sure, you could review the metadata for photos individually, and then resolve the mismatch for each image.
More Detail: The message you’re receiving indicates that there is metadata in the actual photos on your hard drive that is not reflected within your Lightroom catalog. As you can probably appreciate, using the Overwrite option will replace the metadata in the photo on your hard drive using the metadata in the Lightroom catalog for each photo.
When there is a metadata mismatch it means there was an update to the metadata for an image outside of Lightroom. So, for example, you might have opened a RAW capture directly in Photoshop (without using Lightroom), causing Adobe Camera Raw settings to be updated in metadata. Or you might have added some metadata in Adobe Bridge, for example.
If you’re confident that you haven’t performed any metadata updates outside of Lightroom, it is probably safe to simply overwrite the existing metadata for the photos themselves. But you’ll want to be sure that you are truly confident that Lightroom contains all of the correct metadata for the photos.
You can review specific images to try to determine the nature of the metadata mismatch. For example, you can go to the Metadata option on the Library Filter Bar (View > Show Filter Bar from the menu in the Library module). Set a column to Metadata Status, and choose the option to display images with a mismatch, making sure that all other filter columns are set to “All”.
You can then review individual images, examining the metadata in Lightroom as well as with a browser such as Adobe Bridge to confirm there aren’t any metadata values shown in Adobe Bridge that are not reflected in Lightroom.
Once you’re confident that Lightroom reflects all of the metadata you are concerned about for your photos, you can overwrite the metadata for the image files on your hard drive.